Game is enjoyable. Lot of efforts put on shaders.

Be careful concerning other keyboard layout though.. Unity provides customization of input but you hardcoded yours inside the game.

Concerning the music, you could put it on an object that doesn't get destroyed on scene loading so it doesn't reset at every level.

Also, already seen in other games, you could had a bit of text like in the first level each level or every few levels. That could be a good way to tell a narrative.

This game could probably be ported on mobile devices with current gameplay mechanics.