The game is terribly dull. I played it last night on a friends PS3. Its not even like pacman. Heres how it plays.

1) Press X to find green blobs.
2) Stand near blob until it vanishes (signifying you have collected all the people there)
3) Walk back to designated safe zone.
4) Repeat

The entire catch is X is thermal radar, and it doesn't show zombies, so your vulnerable using it, but they're so slow, they pose no threat. I was bored.