CryENGINE 2 was graphically superior to its competition and sported a proprietary new physics engine that allowed for greater realism. However, the sheer amount of processing power required to run Crysis meant that not only could only the best PCs run the game, but that it was completely unusable to consoles. For the release of Crysis 2, Crytek scaled back the graphical improvements of their second CryENGINE and optimized it for the current generation platforms.
For the console release of Crysis, Crytek switched the game's engine to CryENGINE 3 to allow for superior playability on consoles. This did disallow several features of the game.