I think after the first cycle you could have added a bunch of new UI elements like a counter for blocks remaining, the sequence of next blocks, and all that. I also had some issues with inconsistent jump heights, where at some levels I could ascend 3 blocks worth but at other parts I couldn't, which made it a little tricky to do level 2. Also I always had trouble placing blocks high up in level 2 because rotations against the wall don't work right.
Great concept though, and would be fun to see it expanded, perhaps with levels that already start with blocks where you have to use line clears as part of the solution.
Fun "easter egg": after beating level 2, you can jump out the side of the level.