Yup, that's why it's important to try to identify as much of the pills as possible early on. Especially the damage halving one is great to encounter as early as possible since it actually does nothing if your damage is still at one cause pills can't get any stats below that.
Not really, you just got kinda unlucky at encountering him on the second to last floor. Of course everything gets bit more stats on the last floor but no new types. But the demon boss has a speciality skill that he didn't really get to use because of the glitching and there is a normal enemy variant of them as well.