supermario bros.3 world 3 the castle

one of the doors does. i'd recommend reading a guide to it. but i think what you do (if i can remember this level right) is you hit one of the blocks and it will turn into a p-block. step on that, and a door will appear. then you walk into that door. If this doesn't make any sense, just go to a guide, that will probably explain it better

I have an idea. Instead of looking through all the doors, go to the very last door before the third thwomp. It'll take you to a normally inaccessible place and just a few blocks away is the entrance to boom boom's lair. You'll have to climb up the stairs first though.

Door 6