This is a really cool idea. It's a very unique mechanic that is satisfying to use. I like how you have to work with the physics to build a tower that you can climb, it's like you are the level designer. You can't get stuck, and there is always a way to get higher.
One thing that I think could use improvement is jumping on a slope. When the slope is too steep the space bar does nothing, which makes it feel less responsive. I think if jumping on a steep slope would make you jump not as high and off to the side, it would make the movement feel more dynamic and open up more interesting options for traversing your frozen structure.
The music is great, and the visual style fits with it very well. It has great replayability, too, because you will face different challenges each time. I really enjoyed trying out different strategies for getting to the top the quickest and with the fewest frozen boxes.
Thank you for a fun game, qowieury.