I've been running this for a few months, basically I just get one O2 tank for the whole run and while i may upgrade it I can't have a second one on my person. The run forces use of a seamoth and upgrade station to get to the end, making the run more approachable as the only really clinch moment in the run is ducking under the Dragon Leviathan at the end. I think this category can be entertaining to watch and a good start for players wanting to get into speed running but are concerned about their skill level.
My first run was 5 hours but that was just due to having a horrible route. Its down to 2:30 and I think I can get it lower. I also have a video if anyone is interested.
The rules I follow are just hardcore with the added requirement.
I'm probably going to just keep doing the run and posting PBs regardless, as it is super relaxing.