Valve has kept it's promise and made the game more challenging, more fun, and even more hilarious. With more environment interaction, and a brand new Co-op system, Portal 2 will keep you on your toes from start to finish, and even after that. Welcome to Portal 2, the highly anticipated sequel to 2007's Game of the Year, developed by VALVE. Does difficulty affect achievements?: No Difficulty Do cheat codes disable achievements?: No Cheats Number of missable achievements: 30 (15 Single Player / 15 Co-Op) Minimum number of playthroughs needed: 2 (1 for Single Player 1 for Co-Op) Approximate amount of time to 1000: 10-25 Hours (Depends largely on skill)
