By the way, there's an interesting glitch. I saw someone do it in a pyramid level, by releasing the hammer at the right time to destroy only one block (instead of two, I think), then jumping in the small gap that it creates; Mario then starts some infinite fall animation until the game goes crazy. At that point, you can more or less move but can't see much, you can die for no reason, you can pause, etc... The number or lives can change, too. And in the video I saw, the player managed to trigger the end of the level. The glitch has potential, maybe not ACE potential, but still...
In fact, I've tried to find an earlier level to do the same kind of stuff, and I got it on 3-3:
https://imgur.com/zQqTcZB
Here, place the temporary block exactly there (to create that mini-gap), then use an enemy, the key or anything to go and jump from the right in that gap, following the green arrow. If you keep left pressed, the game will end up glitching. From there, well, experiment ^^. I didn't find any use with it, but I just tried random stuff.
