Interesting basic concept. Reminds me of a part from "I Wanna Be the Guy" where you have a platformer hero trapped in a Tetris game with pieces falling.
I think you could have something good here with fairly small changes. I'd like to rotate the pieces, and right now the ladders seem useless because anywhere they'd let the little guy move will probably also get him killed. What if there weren't such a short acceptable fall distance, and there were some Tetris like mechanic encouraging you to place blocks in a certain way, eg. matching colors to get extra draw options?