This is a super cool idea, where the direction you move through the field changes your size, opening up/closing off different areas. I noticed a few things that may be helpful feedback:
- I usually prefer in puzzle games like this when they are less about precise placement and more about figuring out the solution. For example, the first gap requires pretty precise placement of that plank, when I feel like what the game is testing is if you know to use it to cross the gap/know what size to be to place it properly. I didn't like the feeling like I had to line up with the right pixel to place it correctly.
- I think there could be a brief tutorial; even just text on screen to explain controls. I figured it out with guess and check, but it's a nice touch to have it.
- Loved the audio and music, fit the game very well. I like it when music loops after you die, so the player can hear the entire song instead of having to listen to the first 30 seconds of it over and over.
- On the note of dying, it'd be nice to have checkpoints so I don't have to redo the whole stage after accidentally falling into the abyss lol
Overall, I really enjoyed this concept and I think this game has a lot of potential if you want to continue development. The core concept is very engaging, and well thought out. Great job!