Ok! This is a fun game! The best I've played so far with respect to design. Here's a short likes and don't likes list:
What I didn't like: I'm not a big fan of 1 or 2 bit pixel aesthetics. Having said that, you've managed to pull of a very consistent environment for the game. It reminds me of my old ZX Spectrum games so... points for nostalgia. The steering mechanism for some of the enemies often made them stuck in corners. But I guess proper path finding might be too complex for such a short development time. Also, would have taken time from the rest of the design. The multiple save buttons in a single room looked a bit redundant.
What I liked: Pretty much everything else! The level is very well designed. Almost everything that you placed in the level is there for a reason and possible to interact with. This made it a very consistent experience. The special room that one can only access by persistently moving left is brilliant. It was very satisfying to reach it after 3 or 4 cycles (sorry if I can't remember). The small details like having the key follow you smoothly; the small ghosts spawning from the boss ghosts; the contrast between the crawling enemies moving continuously and the ghosts moving in cycles show that you have taken great care and attention to the details.
Overall, an excellent entry to the Jam.