I think it would help if you made the door more obviously into an exit, it was only blind luck that I tried walking into it at one point, after assuming that the game was just broken/buggy that 'getting to the yellow goal' had no effect at all (there's a lot of gamejam games that don't really work, so it's a bold gamble to start with it seeming to be broken :)).
I liked the secrets and mechanics, but playing on laptop trackpad the mouse sensitivity was quickly a pain to deal with and after 8 or 9 levels (out of 1000) I lost the patience to keep going, just a bit too fiddly to work through. Reading the comments seems it got more interesting later on, but ... 1000 levels? ... ouch.