The Steam version, available for $15.99, is a PC-optimized version of the 2007 3D remake for Nintendo DS. On PC, Final Fantasy 4 includes the DS game's voice acting and broader customization system. The game will also support Steam Trading Cards and Steam Achievements, as well as feature different difficulty levels.
Final Fantasy 4 initially launched in 1991 for the SNES and pioneered the Active Time Battle system, turning away from the popular turn-based systems used in role-playing games during that era. In this first iteration of Square's ATB system, time doesn't stop while players select commands, leaving them open to enemy attack and forcing them to think quickly.
Square Enix also recently announced that the Final Fantasy 13 trilogy will launch for Windows PC in the coming months. Final Fantasy 4 is also available for iOS and through the PlayStation Store for PlayStation Portable and PlayStation Vita.