There is a message written at the top of the room next to the 16th floor room. You can see it above the upgrade menu during your fight with the 15th floor.
The random messages you get on top of the screen when you finish the puzzle bugged me out a bit. Stuff like that always gives me the 'something's off' vibe
the problems with this game are: The normal enemies are to easy, The words at the top of the achievements screen are just glitches, The ore to stars ratio is bad, and thats about it so fix these problems.
Yes, there is a cooldown on the powers though!