Firstly, the underflow glitch can not really be compared to the GT code or ACE or anything like that, except aesthetically. It is not a
"major skip glitch", which is an official term here, simply because it doesn't cut most of the previous run's time. The overall time difference is a bit over a minute, and some part of that is other route changes and optimizations. So it's technically a usual case of the
"heavy glitch abuse".
Secondly,
[1368] SNES Super Metroid by Taco, Kriole in 38:41.52,
[1908] SNES Super Metroid "ingame time" by Saturn in 39:15.30, and this submission are all unvaultable, which means that to co-exist as separate branches they have to:
1) be significantly entertaining,
2) have significantly different content with little overlap,
3) have the majority of the vocal audience support the separation,
4) have some definable aspects that could prove that there's really enough difference.
So for those who are super metroid professionals there's a task that would help judging this run properly: please list things that can only be seen in the branch that uses underflow, and then list such things for a branch that would be similar in all other conditions, but would avoid underflow. Because the way I read the thread now, it's the only difference between the proposed two new branches.
I'm asking you guys to help, because even though I generally know the game, I would miss some aspects that are important to a trained eye. On the other side, exactly because I'm not an SM pro, I can evaluate the significance of the factors that the layperson could see, which matters too because we're not an SM TAS site, and we want to meet the expectations of a much broader audience. And finally because SM uses to have exceptionally large amount of branches here. Not that it's a negative thing, it just becomes harder to differentiate between them with the above criteria as that number increases.
