I think you forgot to add it to Any% and the level runs

Where is it? I don't remember.

you unlock it after collecting enough cats, like the other bonus levels.

Nevermind, it's actually called FINAL ANSWER

It's located after level 15. The Any% World Record does it but misses HIDE ROOM 2

Also I don't think it requires collecting cats like HIDE ROOM 1 and 2

I could change the rules and make hide rooms not necessary.

I agree that is the best way to fix this issue. Final Answer should still be required though because it's not really a bonus level.