canadianstickdeath | Skip the Ultra Boots (Deprecated) @canadianstickdeath | Uploaded 9 years ago | Updated 10 minutes ago
EDIT: This is no longer required since you can now reach the key in the flood room without needing the Ultra Boots. So all you have to do to skip them is do the basement legitimately.

The only required use of the Ultra Boots in this game, even glitchless, is to knock down a switch in the flood room, which is currently required in order to reach that room's key. This trick skips unlocking the first door of Bowser's Castle, allowing you to use that key on the flood room door instead.

This seems like it should obviously be slower in All Cards, but I'm curious at least by how much. It saves 4.5 minutes in Chapter 2, skips Ultra Boots and skips the flood room, but in exchange you have to do this trick, take a lower damage output for the last 3rd or so of the run, and go through the entire Ch 8 basement twice (instead of not at all). You could also skip the Ultra Boots by hardening the lava and getting the key there, and then doing a presumably TAS-only Lakilester push in order to get past the block clip without needing the Ultra Boots.

I probably should have rerecorded this video. You don't need to push Lakilester nearly as far as I did. I wasn't sure how much time I was going to need. I also went into the loading zone because I wasn't sure if the lava was going to be solid or not. I also wasn't exactly sure what the best way to get the clippy was, but I think I was fine to win the battle the first time I was in it? If you don't do it right you can easily softlock.

When you get to the Bowser door, the "do you want to get through this door" cutscene walks Mario to the left and inside the blocks there, allowing you to get OoB. Neat little side-effect I guess.

I tried doing something like this in the room before the Ultra Boots for Ultra Boots Early instead. Whenever I would try I would clip out of the block in immediately (if I was ever even inside of it). I also tried using this trick to go over the walls, and though you can get almost to the ceiling, the walls are still higher than you can get. But maybe it could be possible somehow if you did it just right, IDK.