Hi LowQualityRobin,
I'm happy that I tried your game. I had much fun.
I liked that you introduced new mechanics in each level. This is a good way to lead the player without overwhelming him/her. I think the puzzles are innovative.
I also had no problems with the browser version. It runs fine.
The only suggestion I could give you is to make the worlds smaller. Especially in the last level it felt quite long to go from the key to the door.
But other than that. Good game. Very solid. And 3D is a challenge in itself. Good work!