Very nice. Very cute (which is something I like).
The character is cool, but as said, the tiles don't have the same style.
This game is cool. I can be persuaded to contribute and make some tiles if you want, but if you want to do them yourself, I understand, that's up to you.
Another idea I always wanted to see in a puzzle game: 2 player puzzles! These can be played both by 2 players, but also by one player and a "player switch key". Zep needs a girlfriend.
I agree about the somewhat awkward controls a different style would be to hold down space, and press either up, left|right or down to create a block. That way it becomes somewhat more consistent. And you can turn and put out a block in the same go.
I also found a bug:
Build an up block. Then when you walk off it, exactly when you start to fall down, you can build a new up block(!). But Zep will get stuck inside it (falling + raising = 0, I guess). If pressing R, the level will restart but Zep will still be in suspended animation.
I got a bit carried away and really wanted to try to change the look of the game. So I drew some tiles. I hope you don't mind. Do whatever you want with'em.
(It became a bit messy with the blue blocks, so just ignore them. I only wanted to try out some other colors.)
[EDIT 57 or something]
Another cool twist would be to have arrow blocks allready deployed on the map when the level starts. Then the player has to think out in which order to remove the blocks in order to reach the exit. Kinda like drilling through ground.