March 14, 2012 2:00 PM | Lewie Procter
You have to eat a set number of grubs on each level without dying. You can't jump though, instead you have to rotate the world with a tap of the space bar, and hope you don't hit any spikes or enemies. You can get awarded gold, silver or bronze for each level depending on how quickly you do it.
Go try it here. It's described as being "Grub lite", so I guess it is safe to assume a none-lite version is on the way at some point.