Loved it to bits, personally. The graphics weren't really that amazing - the physics on the other hand, are astounding; sets the bar incredibly high for any other game professing to have "dynamic water flow" (I'm looking at you, Bioshock and Hydrophobia).
I didn't have any bone to pick with the gameplay - does what it says on the box, provides a steady stream of new options. Controls were a tad flaky, very reminiscent of Black&White in that regard (in the sense that you din't have pinpoint accurate control of the cursor contextually) but wasn't too painful.
My only real issue is that it was too short... I didn't want it to end. Can't really complain for $15, mind you.