awesome concept! I had a bit of a hard time understanding where the weapon pickups were, and the controls sometimes felt a bit unresponsive, but otherwise I really like the idea behind it! lots of room to explore and try to figure out an optimised path to success!
I did notice maybe a bug, when I found the movement cost reducing potion, the potion stayed in my inventory indefinitely, even after using it. I could reuse it, and the UI would show the counter was active, but even with that after a while it didnt reduce the cost anymore.