Fits the theme well and is a promising idea, but I think it could be greatly improved with a little bit more polishing: Add more SFX, maybe some VFX, and maybe a bit more variety with the monster types (they all seem to just do some damage and have some health), add some meaning to the environment (For example, are the rooms behind doors doing something?) Currently, it is a fun concept, but it seems that all player choices (what monsters and where to put them) lead basically to the same result.