[EDIT] It turns out that the game has been approved by Apple and is on the App Store now.
[App Store Link]
I may be in the minority, but I enjoy sliding block puzzles. I think it's that you can play around with them if you're having difficulty solving the problem, so there's always something to do (for instance the 'get the ball or car out of the blocks' puzzles from the Professor Layton games were among my favourite that experience had to offer).
Prime's Quest looks to put a character in the midst of these sliding blocks, giving him the ability to affect the blocks' size, making it easier to move around. This developer video explains the mechanics and shows off some brief glimpses of gameplay.
The video says that the game isn't due out till June, but it does look nearing completion so we'll see if the date gets bumped up.