The only way to reach Ending 0 (i.e F28) is either by using the 5-Minute Rule (Press Select 100 times on the Main Menu) or the 30-Minute Rule.
TL;DR by Emeraldas
The 30 minute rule / 5 minute rule does not actually count RTA despite the communities prior understanding of the mechanics of how it works. It only keeps track of IGT. Every death adds a 20 second penalty towards the 5 minute timer, meaning collecting 2 backpacks and dying repeatedly will leave you at 1 minute instead of 5. It also doesn't keep track of decimal places so for each level completion that you do it will only keep track of the full seconds that passed. Because of this an optimal run would require a bit of math to fully min max, however this run was pretty sloppy and had a lot of leeway. Its possible that with a perfect run I would not have that leeway and I would need to keep more track of the timer.
The following explanation is from Waka (ワカ)
The first one is an example of entering the door without thinking.
The second one is an example of going to F28 in the optimal time.
If you try to clear the course at your optimum, the time for each field will be quite tight. But even if your IGT is delayed by a few seconds, you should still be able to clear the course much faster than previous runners.
Realistically, it's impossible to enter all the doors in .00 time, so you'll have to settle for around .9X. Since you don't have much time to spare, .7X or .8X should be fine.
I've come up with the best way to deal with dying multiple times in F02 and F10. Use the pause function to adjust the time.
F02: Move to the bottom right of the screen. When the timer reaches XX.06, move left and you'll die at .99. Grab the backpack while you're there.
F10: The first time, if you quickly grab the backpack and fall, you'll be at about .95.
From the second time onwards, wait until you reach .60 before moving to the right and falling.
Additional Resources
Fastests Recorded Ending 0
Side Note: The explanation is incorrect in the video, so use the information in this Guide instead.
Since Emeraldas and Waka have both seemingly "cracked the code" on how the 30-Min Rule works, it seems now it's nessecary to split the various endings into new sub-categories, those being:
- Normal
- 30 Minute Rule
These will also have the unique ruling of allowing "Pause Abuse
