It's never too late to learn how to play Street Fighter.
In Patrick Miller's new book, From Masher to Master: The Educated Video Game Enthusiast's Fighting Game Primer, he helpfully breaks down the genre's basic concepts and game theory into an easily digestible read — even if you haven't seriously played a fighting game since Street Fighter 2 all-but defined the genre more than 20 years ago.
With some help from fellow fighting game enthusiasts, like Skullgirls developer Mike Zaimont, Seth Killian and other fighting game community veterans, Miller explains concepts like mixups and crossups, chains and combos, footsies and reversals, and much more. Whether you want to have a better understanding of how to play fighting games or just want to feel smarter during this weekend's Evo fighting game championships, it's worth the fun, informative read.
We're publishing a slightly abridged version of the book's first chapter with Miller's permission. The full book is available to download for free in PDF format at Shoryuken.com. Versions formatted for ebook readers are forthcoming, Miller said.
Chapter One: Everything You Need to Know About Fighting Games
Street Fighter II is intimidating. Understandably so: Any given character has somewhere between 18-24 different normal moves coming from six buttons (three punch buttons and three kick buttons that each perform different attacks depending on whether your character is standing, crouching, jumping up, or jumping forward/backward), a few throws, special moves, maybe even a super or two.
At any given moment in Street Fighter II, I could conceivably perform upwards of 35-40 different actions. As such, the most useful thing a novice can do is simplify the game. If you learn to think of Street Fighter II as a series of predictable situations with optimal solutions, you can forget the 34 dumb choices in any given situation and focus on executing the one or two good choices.
In rather broad strokes, fighting games are about imposing your will on your opponent. Your goal is to make a series of intelligent situations that constrict your opponent's options, forcing them to make ever-more-dangerous gambles until they do something you can punish them for. You want to put your opponent in these situations over and over until they lose, and then you put them in these situations again and again until they don't want to play with you any more. Basically, you're making the game as tortuous and awful as possible for your opponent while they try to do the same to you. It's a beautiful thing.
To begin: Fighting games are about making your opponent's character lose his life before your character loses hers. Characters in fighting games take damage when you hit them. A "hit" happens when one character presses a button to perform an attack, and that attack connects with the other character's body. These moves are usually different kinds of punches, kicks, and throws, but they range into more exotic stuff like flying uppercuts and fireballs.
While you may be seeing punches and kicks, however, the game itself is just seeing different kinds of boxes moving around. When you hit your opponent with an attack, the game sees your character creating a box that does damage ("hitbox") overlapping with an area occupied by a box that belongs to another character ("hurtbox"). In Super Street Fighter II Turbo HD Remix, you can actually turn on a view mode that shows hitboxes and hurtboxes.
Blue Ryu's hitbox (red) is touching Orange Ryu's hurtbox (blue).
Press medium kick while Ryu is crouching, and you'll see a red box surround his leg. You can see that when you use your normal moves, your character winds up a little bit in the start of the attack, then the hitbox shows up. If your box hits someone, they take damage and are sent into a "hitstun" state for a little while, during which they cannot move, attack, or block. If your opponent's hitbox comes into contact with you either before your hitboxes show up, after your hitbox disappears, or manages to connect with your character's hurtboxes while cleanly avoiding your attack, then you'll get hit instead. If your hitbox hits someone while they're blocking, then they'll be sent into a "blockstun" state, where they won't be able to move or attack but take no damage (unless your attack is a special move, in which case they'll take a little damage for blocking it.
Each attack consists of three phases: "Startup," which is the part of the animation before you project a hitbox; "Active," which is when your attack projects a hitbox; and "Recovery" which is after your hitbox is gone and the move winds down.
This diagram illustrates the length of each phase of Ryu's standing heavy kick.
When you're just starting out with a new character, one of your first steps is to understand each move's advantages and tradeoffs in order to find out which moves are good in different situations. If a move has a really short startup animation, that means you can use it to stop slower attacks before they start and put your opponent under pressure; conversely, if a move has a slow startup animation, you'll have to be more careful about how or when you use it.
If a move stuns your enemy for a long time when you hit them with it, you can use it to start combos and do heavy damage to your opponent (if it hits) or use it to keep your opponent blocking and make it hard for them to start attacking you; if a move doesn't stun your enemy for so long, your opponent might have the opportunity to hit you after blocking it, meaning you should only use that move when you're absolutely sure it'll hit. Some moves cover the area above your character's head, so they're good for hitting enemies that jump at you; moves that extend far across the screen are good for keeping your enemy at range. And so on.
Fighting games are, at their most basic level, really fancy versions of Rock, Paper, Scissors
Note that every move in the game has an advantage and a disadvantage, depending on the situation it's used in. That doesn't mean all moves are equally good; there are some moves that are pretty useless or highly situational, and part of learning a fighting game is figuring out which ones are which. And remember: No matter how cool (or not cool) any given move may look, to the game it's just a different kind of box. So don't pay too much attention to how painful or flashy something looks; often, the coolest-looking moves are the ones you want to use sparingly.
Individual moves are the atomic unit of composition for a fighting game, but eventually your understanding of fighting games will grow to include effective combinations of moves that can work together to mask each others' weaknesses and synergize with each others' strengths in ways that encourage certain styles of play. But before we start understanding different styles of play, we should understand the basic character archetype from which all others are defined: Ryu, the Adam of fighting games.
Ryu vs. Ryu
Ryu is the character that the entire genre of fighting games was designed around. Every fighting game, from King of Fighters to Guilty Gear to Marvel vs. Capcom to Tekken, can trace its design history back right to Ryu. So let's break Ryu down — and in doing so, break down pretty much every fighting game ever.
As it happens, pretty much everything you need to know about modern fighting games is right here in this exchange. We're going to dissect this in-depth, so go ahead and watch it a few times! And don't worry if you can't do all the moves with the precision or timing that you see in this video — we're going to start by analyzing the game flow, and get to the physical execution part later in this book.
Also, I want you to keep one thing in mind: Fighting games are, at their most basic level, really fancy versions of Rock, Paper, Scissors. Any given move in a fighting game is defined in part by what it wins against, what it loses against, and what it draws even against. As you go through this next section, try to think about what each player is doing, and when those actions would win, lose, or draw.
Now, let's start with Phase 1: Orange throws a fireball, Blue jumps over it, Orange hits Blue with a Dragon Punch.
Orange throws a fireball at Blue.
Phase 1: Crouching Fireball, Hidden dragon punch
Ryu's fireball and Dragon Punch are two attacks that are so interesting they basically defined a major chunk of the fighting game genre. The fireball has a fairly high amount of startup time before it turns into a hurtbox. Once it is out, Ryu has to wait for a little bit before he can move freely, and then he can move and attack at will. Depending on which punch button the Ryu player uses to perform the fireball, the fireball's hitbox could be only halfway across the screen or almost all the way across by the time he recovers.
Once Ryu recovers from throwing the fireball, he basically has the ground-half of the screen covered. This fireball leaves his opponent with the following options:
- Get hit by it, leaving him in a short amount of stun and taking a bit of damage,
- Block it, so he takes less stun and damage amount of damage,
- Respond with a fireball of his own to cancel it out, so neither player takes stun or damage,
- Jump over it, avoiding the fireball entirely and opening up an opportunity for a counter-attack.
Essentially, throwing a fireball means putting yourself at risk in the immediate moment (by performing an attack with a long startup period) in order to gain an advantage once it's out and covering a whole bunch of screen space.
So Orange threw a fireball at Blue. How is Blue supposed to find the best option available to him? Well, we'll start by looking for the ideal outcome: Blue wants to avoid taking damage or being stunned. That means that Player 2 can either respond with a fireball to cancel out Player 1's fireball, or jump over it to avoid it completely.
Now, at the beginning of Phase 1, Blue is standing about one-half to two-thirds of a screen-length away from Orange. At this range, it would probably take Blue too much time to a) realize that Orange is throwing a fireball, b) decide to throw a fireball, and c) successfully execute the fireball motion in order to cancel the first fireball out.
If Blue tried to throw a fireball, he'd probably end up getting hit by the first fireball before his own fireball had arrived on screen, or maybe he'd successfully cancel it, but would still be a little bit behind Orange, because Blue started his fireball after Orange did, meaning Blue will recover after Orange — which leaves Orange with time to follow the fireball up with something else, like walking up to Blue and hitting him, or throwing another fireball. So Blue decides to jump at Orange and hit him with a jumping kick.
Unfortunately, this is where the Second Interesting Move In Fighting Games comes in: The Dragon Punch. The Dragon Punch is basically the anti-fireball; where the fireball sacrifices the present for the future, the DP borrows against the future in favor of RIGHT NOW. Upon completing the DP motion, Orange is invincible for the beginning of the move; within a fraction of a second, he absolutely owns the space occupied around his fist.
Once Orange hits Blue with the Dragon Punch, he knocks Blue into the air and sends him into a "knockdown state," where he can't do anything until he gets back up off the ground. Of course, the DP has plenty of recovery time; if Orange didn't hit Blue cleanly with it, then Blue could have punished Orange when he came back down to the ground.
The Dragon Punch is the great momentum-breaker; its near-instant activation time and ultimate priority mean that, basically, if you know that your opponent is going to do something, you can beat it with the Dragon Punch. Your opponent can keep you pummeled under a barrage of fireballs and well-timed moves designed to keep you blocking, but one properly-timed Dragon Punch will reverse the momentum entirely and put you back in the game. However, if you miss a Dragon Punch, you might well lose the game. High risk, high reward.
So, to recap Phase 1: Orange throws a fireball. Blue reacts by trying to jump over the fireball and gets hit with the Dragon Punch, sending Blue down to the ground, where he'll have to wait for a second or two to stand back up before he can do anything.
Hitting your opponent with a dragon punch puts them into a knockdown state.
That puts us into Phase 2, which starts with Orange jumping over Blue's knocked-down body, hitting Blue with a jumping kick when Blue stands up. Blue blocks that jumping attack, performs a Dragon Punch of his own, and gets swept for his trouble. What just happened?
Phase 2: Frame advantage and baiting the DP
Phase 1 ends with Blue recovering from the knockdown that the Dragon Punch caused. During this time, Blue can't take any damage (you can't hit an opponent lying on the ground), but he can't do anything, either. Remember that every attack has a certain amount of startup, and only a select few are invincible during that startup; Orange can use the knockdown period to maneuver himself into an advantageous position, which he does by jumping over Blue's knocked-down body, and starting his attack while Blue is still getting up.
Basically, after Blue gets knocked down, he stands up right into Orange's jumping kick. In this situation, Blue has the following options: get hit, block, or try to dragon punch Orange. In this case, Blue decides to block instead of going for the Dragon Punch (called a "wakeup DP" in this case, since Ryu is "waking up" from knockdown). But why block? The answer has to do with the reason Orange jumped over Blue before starting the kick. Jumping over your grounded enemy is called a "crossup," and it's a very important tactic for fighting games. But before we talk about crossups, we'll have to talk more about blocking.
Blocking is hands-down the most important thing that a beginner can learn
In order to avoid damage, you can block attacks by holding backwards on the joystick. Some attacks must be blocked low (hold down-back) or high (hold back). In general, most crouching kick attacks must be blocked low, most jumping attacks must be blocked high, and most other moves can be blocked high or low. Note that in fighting games, your inputs are dependent on your opponent's position: "hold back to block" means "hold the joystick in the direction away from your opponent," so if you're standing on the left side of the screen and your opponent is on the right, you'll hold left to block, and perform a Dragon Punch by rolling the stick from right, to down, to diagonal down-right, and vice versa if your opponent is on the right stand and you on the left.
Blocking is hands-down the most important thing that a beginner can learn. Remember, your goal is to reduce your opponent's life meter to zero before she can get yours, and if you learn how to block better than your opponent can, you'll have a much easier time to do that! You can't lose if you don't get hit.
Now, let's go back to the example. When Orange jumps over Blue, he makes life harder for Blue in two significant ways. First, he makes his jumping kick harder to block, because Blue has to block in the opposite direction, since Orange is now on Blue's right side, not his left — that's the "crossup" I mentioned earlier. Second, he makes it harder for Blue to perform a "wakeup Dragon Punch" to counter the kick; the proper DP input is toward, down, down-toward, but when "toward" changes from "left" to "right" halfway through the input, it makes it much harder to properly perform. (Some games are more forgiving than others in this regard; Street Fighter IV is one of them.)
Even if Blue successfully executed the wakeup DP, depending on Orange's timing, there is a good chance that it would miss completely, because Blue would still be facing the original direction while Orange would be in the middle of jumping over him, meaning Orange would jump clean over Blue's Dragon Punch and land in time to punish Blue. For Orange, the crossup jumping kick is a very solid decision, because it's hard for Blue to punish.
Note that not all jumping attacks have this "crossup" property that lets you hit an opponent while you're jumping over them, though usually most characters will have one or two moves that make for good crossups. If Orange had jumped over Blue with a move that didn't have a hitbox which let him cross up, Blue simply wouldn't have to block that jumping attack and would be free to move once he was done standing up from knockdown. And sometimes, you might attack with a crossup move that makes contact when you're on one side, but the momentum from the jump carries you to the other, so they have to block your jump attack one way and your followup ground attack the other. Sneaky!
Jumping in with a crossup kick.
So Blue wisely decides that blocking is the Smart Thing To Do, and successfully blocks Orange's crossup jumping kick. Blocking the kick means Blue won't take any damage, which is a good thing, but he's not out of the fire quite yet; Blue is stuck in blockstun for a little while, with Orange standing right next to him. While Blue is recovering from blockstun, Orange can force him to block additional moves that could inflict minor damage ("chip damage," which is incurred by blocking special moves like fireballs and Dragon Punches) and extend his blockstun paralysis, or require a specific blocking input (a low kick that Blue must block by holding down-back, or an "overhead" punch which must be blocked by holding back — Ryu's forward + medium punch, for example), or walk right next to Blue and perform a throw, which is a fast, short-ranged attack that cannot be blocked.
Put yourself in Blue's shoes here, for a second: You just jumped over a fireball, got knocked down by a Dragon Punch, and were forced to block a jump kick that left you unable to do anything. Orange is standing in front of you, but because you're still reeling from blocking that jump kick, you're at a disadvantage because you have to recover from blocking that kick, and Orange doesn't have to.
This means that your next opportunity to attack comes after you've recovered from blocking that kick, and you still have to wait for that attack's startup phase before your attack's hitboxes come out. In fighting games, we measure time in terms of animation "frames"; our games run at 60 frames per second. If Orange's jumping kick forces you to block for, say, 15 frames of animation, and you want to perform a crouching medium punch with six frames of startup immediately after you're done blocking, you'll need to wait a whole 21 frames (about one-third of a second) for your hitbox to arrive.
That might not seem like a whole lot, but in Street Fighter, it's the difference between your crouching punch succeeding, and your punch getting stuffed by pretty much any attack Orange has. This is called "frame advantage" and "frame disadvantage"; basically, Orange's moves have put him in a situation where he has the "frame advantage" because he can start his moves before Blue can start his.
As I mentioned earlier in this section, Ryu has probably about 35 moves or so. In Blue's situation, however, pretty much all of his moves are really, really bad ideas, because they'll get stuffed by just about anything Orange does due to Orange's frame advantage. Right now, Blue can either a) continue to block and hope he makes it out with relatively minor damage, b) get hit, which is not really ideal, or c) try to perform a move. Of the moves that Blue has at his disposal, only one is fast enough to have a chance at beating anything Orange does. You guessed it — that move is the dragon punch.
Now, let me point out something here: As Blue is making his decision here, he's essentially trying to make an educated guess at what Orange is doing. After all, Orange landed right next to Blue after the blocked jump kick; neither player really is far enough to try and react to what the other player does (though eventually, given enough practice, they might be able to). Orange's frame advantage mean that he could decide to walk up and throw, or continue to attack, or even jump again, and Blue will really just have to guess at how to respond accordingly.
So Blue is fed up with blocking and getting hit and generally being beaten up, and decides to go for a Dragon Punch. After all, that Dragon Punch will beat pretty much any button Orange decides to press: If Orange walks up for a throw, he'll get hit; if he tries to make Blue block a low kick, he'll get hit; if he jumps, he'll get hit; etc. And so Blue majestically soars through the air ... and doesn't hit anything, because Orange didn't perform any attacks at all. Oops.
A baited Dragon Punch.
Folks, that's what we call a "baited" Dragon Punch. See, Orange correctly read the situation from Blue's perspective: Blue was tired of being on the defending end, and he knew that he had one option to reverse the momentum, which was the Dragon Punch. From Orange's perspective, he could either choose to attack, and risk getting hit by the DP, which would have knocked Orange down and shifted the momentum in favor of Blue; or sit there and do nothing, which would either reset the momentum back to even, if Blue decides to block, or give Orange another opening, if Blue decides to do a Dragon Punch. Basically, Orange took a conservative tack by not taking the risk of getting DPed, and his read of Blue turned out to be correct. Once Blue lands from the DP, Orange sweeps him, knocking him down again and bringing us into Phase 3.
Phase 3: the close-range high-low-throw mixup
Poor Blue just can't catch a break. His perfectly-timed counter DP ended up getting baited and punished, and he gets knocked down again. This time, Blue blocks a few light jabs from Orange before getting thrown, knocking him down yet again and setting the stage for further pain. What happened?
At the beginning of Phase 3 (after Blue gets swept), he's basically in the same position as he was after getting DPed at the end of Phase 1, except this time he doesn't have to block the crossup jumping kick — though, depending on timing, Orange probably could have made him block that if he had wanted to. Once again, Orange has the momentum, because he can start setting up his attacks while Blue is still standing up from the knockdown.
Step into Blue's shoes for a second, now, and feel what it's like to be well and truly broken. You dodged a fireball and got hit; you tried to counter a whole bunch of attacks that never came and got hit. Orange is pretty effortlessly making you look like an amateur. You want nothing more than to be out of this situation, but Orange seems to be reading your mind re: potential get-out-of-jail-free Dragon Punch opportunities, so you've resolved to just hold back and block until the danger is over.
After all, he can't keep you in blockstun forever; block enough attacks, and Orange will eventually be pushed out far enough that the momentum will reset and you can take another stab at winning this game.
Which is why Orange throws you. Because he knows you're broken. He knows you can't muster the will to try another counter Dragon Punch. So he walks up, makes you block a jab or two, and then takes a step forward and throws you, dealing a solid amount of damage and knocking you down.
Setting up a throw with the jab ("tick throwing")
The throw is typically performed by walking next to your opponent and pressing forward or backward and heavy punch or kick. (Some characters have additional throws as well, but everyone has those two.) Throws exist to stop people from thinking of blocking as an invincible wall behind which they can hide from attacks. As it turns out, blocking attacks gets pretty easy pretty quickly; you just crouch-block everything except for jumping attacks and "overhead" attacks (standing attacks which force you to block high), both of which you should be able to react to if all you're thinking about is blocking. By adding throws into the mix, the attacker gets to crack a determined blocker by making him block one jab, then throwing him; or making him block two jabs, then throwing him; or three, or zero. A determined blocker can escape a throw (called "teching a throw") for low or zero damage, depending on the game, but in order to do so they basically need to go for a throw at the same time or slightly later than the attacker's throw, which is tricky. Orange forced Blue to block a fast, light attack, then threw him. This is called a "tick throw."
When Ryu knocks you down and stands right next to you, he has a whole bunch of options: He can make you block low, he can make you block high, or he can throw you. As the defender, your job is to either dragon punch (at just the right time), or defend the incoming throws and attacks until you see an opening to counter-attack or escape to safety. This is known as a "high/low/throw mixup"; the defender is basically put into a situation where he probably won't have time to react to seeing what the attacker does and defend accordingly, so he has to guess whether the attacker is going for a high attack (block high), low attack (block low), or throw. Even worse, the attacker is forcing the defender to make these decisions at an extremely fast rate; if Orange forces Blue to block three jabs, he could have easily at any point made one of those a low short kick, or a throw attempt, or ended the string with a high attack. Obviously, as the defender, you want to avoid these situations as much as possible. In this case, Blue got thrown, which resulted in moderate damage and yet another knockdown.
Phew! We just analyzed a mere nine seconds of high-speed decision-making, and all of that started from one fireball. One humble fireball, coasting across the screen, enabled Orange to keep Blue constantly on the losing side of the decision-making process. By now, you can see how that happened. But why'd Orange throw the fireball in the first place?
Phase 0: Fireballs, footsies, and jockeying for momentum
Earlier in this article, I described the art of playing fighting games as, more or less, "making the game as miserable an experience as possible for your opponent." You can see how Orange did that; he threw a fireball that got Blue to jump, and that one ill-timed jump sent Blue into a cascade of unfair decision after unfair decision. The right fireball at the right time gave orange command of the match — in other words, momentum.
But how do you get that momentum? Certainly not by throwing fireballs willy-nilly; if Blue had predicted the fireball and jumped in earlier, he could have easily landed a damaging combo into a knockdown and sent the momentum in his favor instead. The art of jockeying for position is where much of the beauty and skill of fighting games comes into play; recently, people have been calling it "the neutral game." We can broadly define the neutral game as "the process of turning an equal situation into an advantageous one."
Understanding the neutral game is important for a budding fighting game player because, frankly, this is where you lose the game; it doesn't matter how good your combos are or how clever your high-low-throw mixups are if you can't get that first knockdown you need to set them up. And when you start playing fighting games, it's easy to focus on spiffy special moves and combos without thinking too much about how to create openings to land them.
Let's travel back to the beginning of the match we watched earlier and break down each character's options. From the very start of the match, both players start at a range referred to as "half-screen," where neither player can hit each other with anything except for a fireball or hurricane kick (Ryu's third special move — don't worry about this for now), and neither option is particularly good.
Ryu at half-screen distance.
When you're at half-screen, with no frame advantage, it's pretty easy to see a fireball starting up and punish it with a jump-forward kick and combo from there.
If either of the Ryus takes a step forward from half-screen, they'll be within range to sweep each other, which would give one of them the knockdown he needs to start his crossup / tick throw shenanigans in close or pressure with fireballs. If he's walking closer still, he'd be within ideal range for fast, weak attacks (jabs and short kicks) to set up throws, but it's typically rather unlikely for both Ryu players to just close the distance like that without one sweeping the other first.
If one of them instead decides to take a step or two back from half-screen (we'll call this range "two-thirds"), he'll be in prime fireball-throwing range for one major reason: At this range, you're too far to react to seeing your opponent start throwing a fireball by jumping over, since by the time you're jumping over that fireball, the fireball-thrower has already recovered in time to Dragon Punch you out of the air, because the fireball has had to travel further to reach you. In order to punish a fireball with a jump attack at this range, you'd have to start your jump around the same time they start throwing the fireball, if not earlier — which means you're anticipating a fireball, not reacting to it, and if that fireball doesn't come, you're probably just going to eat a Dragon Punch instead.
However, at two-thirds screen range, you are roughly around the area where you can respond to a fireball with a fireball of your own on reaction. You will recover after your opponent does, since you started your fireball later, giving your opponent a slight advantage, but that won't be a big enough advantage to punish your fireball; they might just be able to take a few steps forward (into half-screen range). You can also instead choose to jump straight up over the fireball, which is usually the smarter choice because you don't risk getting Dragon Punched (you're still too far away), and you don't have to block anything, meaning you take no chip damage or blockstun, so you recover slightly faster from dealing with that fireball.
Further back from here is the full-screen range. From here, neither Ryu can do anything except throw fireballs, and neither player is likely to get hit by a fireball from full-screen. From here, you can safely jump over an opponent's fireball, because even if you jump forward, their anti-air Dragon Punch won't hit because you're still too far away.
(By the way: It's worth noting here that all this knowledge about what is effective at any given range isn't something you're expected to know right off the bat. This is the kind of thing you generally have to learn the hard way.)
In a Ryu vs. Ryu mirror match, he doesn't have many good options at a neutral two-thirds or full-screen. He wants you to be at two-thirds when he has an advantage, because that puts you in situations where you're likely to either block a lot of fireballs or jump forward and eat a Dragon Punch, but in order to put you there, he's going to have to knock you down first.
So both Ryus start at half-screen, and both of them need to knock the other down — probably with a sweep. You might think that the best thing to do at the start of the round, then, is "walk forward a step or two, then sweep." However, remember that you're both playing Ryu, and you both want the same thing — so it gets a little complicated. If your opponent knows that you're going to walk forward and sweep, they could sweep first, which you'd probably walk right into since you decided to walk forward. Or they could walk backwards to stay out of range of your sweep, and if they see you whiff the sweep, they could hit the tip of your outstretched leg with their own sweep. Or maybe they stay out of sweep range while you're hunting for a sweep and make you block a fireball. And so on.
This kind of game dynamic — dancing in and out of range while fishing for hits to turn into an advantage — is called "footsies." If you can react to everything, you can be a god at footsies, but if you can't, you'll find that you have to rely on your ability to read your opponent in order to give you the extra time you need to play footsies well. After all, some people will be more aggressive, some less aggressive, some better at reacting and some less good at it. It's like playing poker at a very, very high speed, since in every fraction of a second you're making new decisions: Attacking or not attacking, staying at range or going closer/further, and so on.
If that wasn't enough to twist your brain into knots, consider how hard it is to detect bluffs in high-speed poker; that is, players will often be doing things to trick you into overextending yourself. Watch any high-level fighting game matches and you'll see them walk back and forth rapidly — they're quickly dancing in and out of range to bait the other player into, say, starting a fireball because they think it's safe when it's not, or pressing standing light kick at a range where it's unsafe to throw a fireball in the hopes that you'll react, think they're throwing a fireball, and jump in for a counter-attack (which will then get Dragon Punched). Basically, once you've learned what you're supposed to be doing (knocking your opponent down) you have to think about how to make it look like you're going for a sweep so that your opponent will try to sweep you, and so on. Mind games!
Once you get the knockdown, you can go for a crossup jump kick into some up-close shenanigans, or you can throw a jab fireball that is timed to hit them right when they stand up and immediately follow it with a heavy fireball — which starts a classic fireball-Dragon Punch trap that SF veteran David Sirlin describes in chapter 1 of Playing To Win way better than I can, so go read it.
Fleshing out the Fighting game design skeleton
Everything you've read about so far has been the essence of the modern 2D fighting game; the core upon which everything else is built. By itself, it is perfect — even better than Chess, perhaps, since Chess requires one player to move first. But it's not quite so easy to sell Ryu vs. Ryu: The Game, so instead we have not-Ryu characters and not-Super Turbo games to flesh out that core skeleton.
Ken, of course, is a tweaked Ryu; in Super Turbo, he has a high-damaging throw (the "knee bash" ) that gives him a lot of options after he finishes it, and a Dragon Punch that has more invincibility frames, less recovery, and more horizontal range, plus a few different kicks that give him more varied footsies options. However, his fireball doesn't travel as quickly or recover as quickly as Ryu's, making it harder for him to pressure opponents at far range or hold up against sustained fireball pressure from characters with faster fireballs. Also, Ken's hurricane kick doesn't knock down on hit, meaning you don't get an easy mixup after comboing into it.
The sum of these combinations typically make Ken a better character for less-patient players looking to easily punish jump-ins and use knockdowns as opportunities to land throws. If you play a few hours of Ryu vs. Ryu and find your best success with close-in pressure games, give Ken a shot.
On paper, Guile might appear to be very similar to Ryu; he has one move that's good for beating jump-ins (flash kick) and a projectile (sonic boom) that's good for pressure. Guile recovers ridiculously quickly from throwing his sonic boom, but it travels rather slowly, and in order to perform the sonic boom, the Guile player needs to "charge" back (hold back or down-back on the joystick) for a moment, then press forward and punch.
So Guile can't win a fireball war with Ryu or Sagat, and he can't quite freely move around the screen because a good Guile player needs to always be holding down-back on the joystick to keep a sonic boom or flash kick at the ready. Much of the time, this means that Guile needs to use his low-recovery sonic boom to close the distance; if Guile can walk behind his sonic boom, he's basically covered by a shield.
Guile can use his low-recovery Sonic Boom to cover his approach.
If Ryu blocks that Sonic Boom, Guile is in range to throw; if Ryu throws a fireball of his own, the two projectiles will cancel out, but Guile can hit Ryu out of his late fireball recovery with his spinning backfist (toward + HP). In short, Guile's character design is a combination of his moves' properties (low-speed, low-recovery projectile) and the actual physical inputs, which restrict the player's freedom of movement (the charging mechanic).
And so on, and so on, for Balrog and Dee Jay and Blanka and the rest of the cast. Pretty much every character must have a different answer to the question: "What do I do when Ryu throws a fireball at me?" Some characters have excellent options for dealing with fireballs, but aren't so dangerous once they get in. Other characters have relatively bad options, but if they do get in, you're in trouble.
And it doesn't stop there. Each subsequent Street Fighter game sets up the Ryu fireball threat differently: The Alpha series makes you work harder to find openings, since you have more defensive options, but give you more tools to put together higher-damage combos. Street Fighter III pretty much got rid of the fireball-DP dynamic altogether by introducing the Parry system, which basically makes fireballs close to worthless — and so Street Fighter IV took part of that and made it weaker with Focus Attacks to make fireballs worthwhile but not game-defining. SNK's King of Fighters introduced the short hop, dodge, and roll systems to give players more options for getting around fireballs (each of which, of course, have their own respective weaknesses as well). Heck, we can even think of the Vs. series (Marvel vs. Capcom and such) as asking the question, "Well, what if Ryu throws a fireball at me in a two-on-two or three-on-three tag match?"
In case you were wondering: This is most likely why in practically every 2D fighting game ever, (okay, an exaggeration — but a LOT of fighting games) the "main character" for the game — the one that the first player starts out highlighting at the character select screen — possesses a similar fireball/DP moveset. That way you can start learning the game by playing Ryu, see what moves and systems the game gives you to deal with the fireball/DP problem, and begin to build an understanding of that particular game's design and mechanics based on what you know about Super Turbo.
Congratulations: That's everything you need to know about Street Fighter! Well, not really, but it's enough to get started. I'm going to give you a little bit of homework: Go find a friend and play Ryu vs. Ryu for an hour or two, and then come back and read some more.