This one has so much checkpoint abuse going on that following the route is difficult/impossible, so I added a visual guide of sorts to the left of the run which should hopefully make it a bit easier to understand what's going on. There's also an explanation below.
At 0:17 and 0:26, I land/crash into the railing in such a way that, for some reason, I get knocked out-of-bounds and eventually on to another part of the track. This has an important side-effect of causing the game's checkpoint system to think I'm on the outside ring (where I last landed properly) while I'm actually at the start of the inside ring (where I got pushed on to).
Normally when you go airborne on one part of the track and land on a completely different part of the track, the game updates the checkpoint correctly every single time. But because this glitched bonk off the rail doesn't put the machine in an actual aerial state (even though it looks like it's hovering in the air), the game doesn't see a reason to update the checkpoint if the machine happens to "land" somewhere else, so the checkpoint is basically hooked/stuck on the outside ring. Despite this, the checkpoint system still tries to follow me as best as it can, so as I move up/down or left/right in the game world, the checkpoint value updates accordingly if the track layout allows it.
This can be used to utterly break Double Link, Mist Ring and Puzzle Ring...but I'm only TASing Double Link.
The first instance of this glitch is used to remotely trigger the start of lap 1 while on a much later part of the track (to clarify, each race starts at the very end of "lap 0", so until I cross the finish line, I haven't actually started lap 1 yet). Shortly after crossing into lap 1 for real, I hit the jump-plate and go airborne.
While airborne, the game checks if I'm directly above any part of the track, and if that is the case, then it updates my current checkpoint to that part of the track, effectively de-activating the glitch.
On the frame that I go airborne, I'm still directly above the jump-plate which is enough for the game to change the checkpoint to the correct value, but since I didn't interact with the finish line during this period, the lap count remains unaffected. In other words, as far as the game is concerned, I just skipped from from checkpoint 6 to 126 while still on lap 1.
This "skip" ultimately saves ~7 seconds.
(Note: it's not at all necessary to be directly above the jump-plate after going airborne for this skip/strat to be successful)
I could've taken my ~7 second timesave and landed on the road properly to finish lap 1 normally, but instead I immediately perform the glitch again just as I land to remotely start lap 2. This is so I can start the new lap right near a jump-plate which can be abused to finish both boost-laps in under 2.5 seconds a piece using "regular" broken Climax checkpoint logic lmao.
The beauty about the fact that this checkpoint glitch can be undone by simply flying directly above any part of the track is that I don't have to worry about accidentally going backwards into lap 1 while attempting to jump behind the finish line during lap 2.
The checkpoints in lap 3 all behave as normal.
One last thing: this glitch could potentially be done by simply driving into the rail in the right spot, as seen here: • What's a Wall? (F-Zero...
So far, I haven't been able to replicate this on MFDL, with or without boost power. If this could be done on lap 1, then there might be room to improve this TAS.
Re-records: 19,574 (...oh...that's a lot more than I expected)
Input file (.bk2):
www.mediafire.com/file/q5qxbx...
^Synced on BizHawk 2.4.0
TAS history:
37"36: • Mist Flow - Double Lin...
^ This run isn't properly optimised, but since it goes through most of lap 1 the intended way it should be a bit easier to follow.
59"05: www.nicovideo.jp/watch/sm7952862
^ An old TAS but it's still fun to watch imo.
World Record by Go Mifune (57"28): • F-Zero Climax Mist Flo...