Not bad! It was fun to figure out there were walls that changed/ could be walked through. I'd definitely fix the mouse not being fixed in the game when playing in webgl. Also, mazes can be quite tedious, since they do make you feel lost, its very easy for a player to want to give up. So maybe add some features around engaging the player more: a sprint mechanic or some scripted event that shows the walls moving. Anyways definitely a good first try!