Ok...
First off, I didn't play all the levels. I got so pissed at 19 (I believe it was) that I quit playing altogether. There was no progression into this level of difficulty. I went from the puzzles solving themselves to level 18 being a good challenge and 19 being fucking impossible. Sorry, it's just that there's a part where you have to jump onto the block that you've been riding in the double gravity tunnel (or whatever you want to call it) and then up over a couple of little blocks with spikes beneath them and I could swear that I've cleared it but I die. After acing the first 10 minutes of the stage and then making a jump I'd swear on my life I made and dying so many times I decided it was best I quit before I throw my computer across the room.
The first stages were almost insultingly easy and then you get a stage like that and it really ruins the game. There needs to be a good balance of difficulty that is both challenging and do-able by the majority of people to keep interest. If you have 35 stages, 10 of them at max should be of the solve themselves difficulty. And that's just to illustrate how the damn game works.
Aside from this, the game was fine. Controls responded well. Dialog was cheesy but not terribly horrible. I wanted to like it more. I would have finished it if it weren't for that. I don't mean to rant about the same problem over and over but it's just so frustrating.