Revealing mistake: Right before the Creeper punches the hole in the bus roof, the outline reveals where the hand shall come through. (00:47:00)
Revealing mistake: When the creeper has the pole through his eye and is pushing it in and out, the pole appears to be moving however there is a clear dot on the pole that stays where it is in relation to his face. (00:50:20)
Revealing mistake: When the kids are running through the cornfield, how can it be they cast two shadows? At night in no mans land there is only one light source, the moon (and even the moon wouldn't shine so bright). (01:06:40)
Revealing mistake: When the Creeper is chasing Izzy, Rhonda and Double D in the truck at the end, during the overhead shot of Izzy pulling off the road you can see the tire tracks from previous takes. (01:22:50)
Revealing mistake: When the pickup truck stops short and the Creeper goes through the cab, the truck flips over frontwards. If you look near the rear axle when it flips over you can see the puff of white smoke and the cylinder that helped to flip the truck.
Revealing mistake: When the group is running on the field, before Scotty gets his hand stabbed to the tree, there is a shot of a girl running and behind her all the others are blurred, as if its a green screen.
Revealing mistake: When Izzy pushes Rhonda out of the moving truck, if you watch in slow motion you can see him pretend to open the door and then just push Rhonda down to the seat, out of sight.
Revealing mistake: When the Creeper has been harpooned, he flies in the air dragging the pick-up truck with him. The pick-up truck moves towards the back of the school bus. If you look carefully you can see that the cable attached between harpooned Creeper and pick-up truck at times hangs too loose to be able to pull the truck, so obviously the truck is moving on its own (with hidden mechanics, which you by the way can't see).
Answer: Eating human flesh helps the Creeper regenerate his whole body, no matter which part he ate.
Celldweller55