Portal 2 fan Patrick Murphy has created an unofficial expansion to Valve's highly successful first-person puzzler called Designed for Danger.
Designed for Danger adds eight levels to Portal 2 and takes the player down an alternate path to what they would have experienced in Portal 2. The levels take one to two hours to play through and can be downloaded free of charge here.
Players can choose to download the expansion via Steam Workshop or through a mirrored server. The levels are playable on the Steam version of Portal 2.