Not anything specific, but I thought I would throw this out anyway. I recently watched a video explaining how the game loads warp zones and how the minus world glitch works. In case you don't know, the glitch is caused by having the game load the wrong warp zone (4-2 underground) and consequently takes Mario to a glitched world. It then dawned on me that if a glitch similar to this allowed you to load the 4-2 aboveground warp zone underground, you could take the left pipe and be taken to world 8, entirely skipping world 4. In order to do this we would have to trick the game into thinking we were aboveground, which doesn't seem possible. But if we can figure out a way to do this, then I do think that such a skip would become possible. Again, it's only a theory

Smart thinking, although the odds of being able to do such things to the game are very, very slim. Maybe we could use a TAS first to figure out the 1-2 & 4-2 tricks, since you can munipulate every frame of the game.

TAS is definitely the way to go, although I'm by no means an expert with it. I would have to leave that to members of the community who know what they're doing

I think this theory was very good. To go to the the World 8 by just going to the world 4 pipe, it needs or we need to understand the hex value of how pipe works and glitching the game to think that way. This still need alot of work to do it.

If the entrance value is stored as an entity like an enemy it's possible that we might be able to do some fancy stuff with unloading and reloading or something but I seriously doubt it.

I've looked in to this a bit and sadly it doesn't seem possible. where the warps take you is stored as a byte which is seemingly unaffected by anything other than your x value in relation to the current level. I'll look into it more and let you know what i find, but it isn't looking good at the moment.

Okay, update. I've found that there are TWO addresses in memory that need to be at specific values. first of all, you were correct in assuming that we would need to make the game think we're above ground. BUT we also need to trick the game into thinking we're on world four or higher. so, now that i have the specific variables needed, ill look into possible manipulation tactics.

Had no idea about that second variable. Seeing the minus world having a level from the original game in the wrong background (-3, an underground world which should be a castle) gave me hope that this could become reality, but now that it's more complicated, I'm not so sure anymore