(Continued because of size limitations.)
UPB Sadist should probably be named Masochist instead, honestly. It's a symmetrical stage in which you have to clear out almost everything to unleash the target, a Longai-O. There's a core under his gate so you can control when he's unleashed if you want. There are fuse-opened rooms in the corners, the lower two of which must be cleared out. The upper rooms have max health powerups if you need them, but they're guarded, so you should save a couple of bombs for the occasion.
UPB Double Climb simply requires you to take a box all the way to the top of a tower, then go back and do the same thing on the other side of the tower. I tried to mix up the challenges quite a bit on the two sides, not to mention prevent cheating by pushing both boxes up the same side. There's no puzzle to it. I was just trying to add a new wrinkle for time attack purposes.
I'm working on a stage that's simply about surviving until a fuse reaches the target, but I'm stymied by the inability to make spawners invulnerable, or even spawn more spawners. I've already managed to clear the whole stage before the fuse runs out.