Did you play 0.9.0 or 0.9.1.2? The balance is better in the new version. I brought up the issue of the mermaid boss heals in the old version.
I was playing in 0.9.0 and my bad, I didn't read your past comments as I was still having my first playthrough and didn't want anything spoiled.
I'm glad the healing issue with that boss is fixed.
Another thing, is my gallery completed with all the current fights? (still 0.9.0)
I don't know if the middle holes are supposed to be there, so I would like to know if I skipped some encounters (most likely).
I remember there being an enemy that interacts with you when you sleep but I don't think I've fought it.
Also, as you can see from the image, the duo fight against the mermaids is missing. Maybe it was fixed in the latest updates, but the duo only shows in the defeat scenes.
One of those center squares is taken up in 0.9.1.2, the boss added with that version. The other two are not added yet. I'm assuming the squares on the lower right are also for future enemies, like the Casino Bunnies.
The Duo Fight with the mermaids might be the only one working properly as a refight, as it's a known bug that visiting the recollection room will unlock all of the fights. Finding that fight shouldn't be hard, it is in the main tower.