I actually really like the concept of this one. It takes a very different approach to the other games I've tried so far, and when the twist comes (I don't want to spoil it for others) it comes by surprise and has a lot more impact than if the whole game had been like that. That being said, I think the Custom Level and Credits text do kind of break the illusion a bit early on.
It also has some of the more clever implementation of the theme I've seen, and (deliberately or not) is implemented twice two different ways.