Old school style Finger Munch, they are all hungry, some smarter than others, feed them, kill them, let them entertain you for a while.

Creatures:
White-just hungry
Green-paranoid and hungry
Yellow-hungry predators but know when to run away
Red-hungry predators

Food:
Blue-make them move faster
Red-poison that kills them
Green-mate food

Things moving too slowly, switch to finger feeding mode and speed the game up. Tip: keep them all alive for as long as possible to achieve a good score.