Interesting mechanical idea (you can only move when jumping), and the game looks kinda cute!
I did have a lot of trouble playing, however. Some feedback:
- I couldn't press two keys at the same time. So if I jumped and didn't immediately let go of the jump button, I couldn't move. I don't know if this was a design choice (made on purpose), but it just meant I had to sometimes try four or five times before I could jump + move.
- Additionally, if I just held the "A" or "D" key as I fell down, I could move without having to jump. As soon as it touched the platform, it would keep sliding.
- It wasn't clear that keys made you jump higher. I tried for ten minutes to grab the key in the bottom left corner on level 1, asking myself: "Am I doing something wrong? I just cannot get the key!" I was about to give up, until I realized there was another key I could grab, which made me jump higher.
- On that same note: once you fall down on level 1, you just cannot do anything anymore. You don't have enough jump height to grab a single key.
- Talking about that ... I didn't find the use in rotating? Maybe I'm just stupid, but I couldn't figure out how to use it. You also rotate extremely slowly, which didn't feel right (can't say exactly why).
- If you are rotated, however, the hitbox/body of the player doesn't align anymore. When upside down, my head kept sinking into platforms for a good amount of pixels :p
- Minor stuff: maybe rename "About" to "Tutorial" or "Instructions". And when I started level 2, I started too high ("above the actual level"), which meant I was falling through black darkness for a second or so.
I hope you don't find this feedback too harsh, just trying to help :) You're on the right track, just needs some finetuning. Keep making games with interesting mechanics :)