@Windwalker Nothing too special. They use LineOfSight and when they see the player they store it's x position and if they don't they move to that x position. Also they use 3 stages idle, seek and attack.
There is still room for improvement but I haven't planned anything too complicated.
@Windwalker You're welcome. Right now bullets use Bullet behavior but I will change them to use loop (something like, if not overlapping whit anything move one pixel forward and loop 5 times). That way there shouldn't be any frameskip problems. Only grenade uses physics.
Also shells and ragdolls disables physics after a while.