Anyone up for a round of World of Crycraft? Oh... no that was another movie...
Seriously: I think I've read before Crysis would have sequels and seriously: They could have used Cryengine 1 if they had liked to produce Crysis as a single game. The fact they have developed a new engine was a sign for a whole series at first glance (no one produces a new engine for like 1+ million dollars per license if he doesn't use it)