This game is pretty nice. A few ideas.
1. the boxes fall a little after you die in the level. If this is unintentional, its ok! It helps feel really nice/
2. Difficulty. Its HARD. Something to correct air movement early on would help a LOT.
3. Jumps. Feels a bit floaty, not terrible, but definitely something
4. Side clips. If you hug a wall, you can instantly jump in the air. It feels a bit... off, but could be used for something =)