I based my thing of the stage 2 boss room:
This more or less started with an idea for a palette cycling animation. I hadn't taken the 16*16 areas rule fully into account, so I discovered halfway through assembling the animation that I didn't align the windows right and that they wouldn't work in this setup at uniform length anyway. Not without having to remove the window frames.
This requires three out of four palettes, so the rest of the room had to be monochrome. I got a bit lazy with the foreground. The doors look rather poor to me now as well.
I haven't made a animation going from the static version to the cycling, although I have one planned. The head wouldn't be around anymore during the animation in-game.
Before I fix anything or work on the forground though, I'd like to know if the cycling and colour choice looks good. Other comments are welcome as well.
These are the current tiles, by the way:
This version should obey restrictions. Also messed with some tiles. I guess the doors are pillars now.
Current tile use.