#712 BIG BOO CASTLE
Secret exit: No
Yoshi coins: Yes (5 to find)
3-up moon: Yes
(Also included is my usual GYRB Switch Palace, since I did put some ! blocks in my level.)
I kinda rushed to get this one done in time, since I didn't really start working on it until a couple days ago. I did test it thoroughly, but it's always possible that there's a problem I didn't spot.