Edit: The original post had issues due to a WC2 soft-lock, but due to new ESW discoveries, this is viable again. Even more viable now that K4 Early works.

We can save significant time by running the game with two files, and using ESW to warp between them.

Here is the PDF route https://www.speedrun.com/sfa/guide/m3cys

Edit: The final ESW causes a soft-lock, so this video is no longer valid and doesn't save time. Just keeping it here for historical reasons.

NOTES:
1) K3 early and DIM can be done in either order. Perhaps just do whichever is easiest to choke first -- Test of Fear vs Seam skip.
2) Getting Freeze Blast later is now possible (during SS3 turn in), but doing so loses time. This is because you MUST open both SS1 doors & flame the grates. Skipping any of these results in a soft-lock when placing SS3.
3) Skipping SS2 does not seem to be possible. The SS4 warp pad does not fully load until after SS2 is placed.
4) It may be possible to skip the water block puzzle entirely if we can swim past it. I couldn't find any setups. Swimming around it results in void outs, and there is no wiggle room.
5) If we find a way to swim into the temple, we can skip the first RNG puzzle. Unfortunately, it would only skip the SS2 version of the puzzle.
6) Approaching the water block puzzle from behind opens the gate if it is closed

Cape Claw OOB navigation tips:
- The right side of the mouth (when facing statue) seems easier to set up the air swim. Do not go too far in or you will clip inside and get stuck.
- You can gain height before the puzzle room as long as Cape Claw is loaded instead of the puzzle map
- It is much easier to navigate the west side of Cape Claw (side shown in video). Less potential void outs. It is also easier to set up the camera for gaining height in the water block puzzle.
- Be VERY careful how you clip into the puzzle room. You want to approach the climbable ledge from the left side. Otherwise, Tricky will spawn below, and you will lose time because you will have to raise the water.

idk if you also took this into consideration but K4 Early would also be possible to do with ESW which would save an additional 16+ minutes because DIME would be possible as well.

I updated my guide (https://www.speedrun.com/sfa/guide/m3cys) with a 1st draft of a new Fuel Cell route. It's pretty hard to figure out since Ocean Point 1 and 2 are done after Dragon rock. This means the Fuel Cells there are useless.

Fuel cells that are no longer viable:
- 4x in Ocean Point
- 2x on the way back from Cape Claw (boost pad by LFV)
- 1x in Cape Claw from dropping down on the way to the waterfall. It's no longer optimal for the route.

Candidate replacements:
- 4x on River Path in SnowHorn wastes
- 2x in Volcano Force Point. 1 under bridge (adds 12s), 1 before the warp to placing SS3 (adds 7s).

The run back from Cape Claw #1 and a Death Warp ESW are actually pretty close time wise I think (needs confirmation). I think running back is 20s slower (an additional 12s slower if the 2x Fuel Cells are collected)

However, on the 2nd trip to Cape Claw, not only do we not have a choice due to a soft-lock, but we also skip a long cutscene, which makes ESW optimal.

Your video ends when you go to Walled City 2, but I'm wondering if it can get into Krazoa Shrine 5.

Shit. Moon/Sun stones can't be placed. Any idea what went wrong?

Left: ESW, Right: Any%

It does not say "Placed Final SpellStone". Perhaps skipping Fire Gems is an issue? LFV? Should K3 be placed after placing SS2? So many things to test. Brutal.

EDIT: Oh, we skipped the cutscene with the Queen returning to Thorntail! Maybe we just need to activate this.

EDIT 2: Still not working, but talking to the Queen fixed the text:

I don't know anything so I'm going to test.

I tried using a position hack to leave after placing SS4. This worked! Walled City 2 loaded correctly after running back from Ocean Point.

Somehow using ESW to leave Ocean Point causes problems.

I confirmed that walking back solves the problem. Perhaps ESW corrupts the save file? We can avoid the soft-lock, but it reduces the time save by 4-5 minutes due to an extra trip to Cape Claw.

Results of my test.
When Walled City 2 is triggered, some bits of address 003A44C8 will change in 1.1 USA version.
The trigger for Walled City 2 is the placement of SpellStone 4, regardless of the Queen EarthWalker cutscene.
On the K3E route, Walled City 2 is triggered correctly when SS4 is placed, but ESW destroys the file and disables Walled City 2.

Is DIM the only possible ESW location? Maybe we can ESW somewhere else to avoid the corrupted file.

ESW is possible in all places where Fox will be placed after Fox's death but where Fox will not be placed after file is loaded, probably.

I found one on Dinosaur Planet after turning in K3. Perhaps this will not cause issues:

Maybe this will improve time saves even more, since it can cut out unnecessary space flights, and save time running back from Volcano Point / Cape Claw / Ocean Point / SnowHorn Wastes / Walled City

A lot of travel can be replaced, assuming there are no bullshit soft-locks. I'll test to see if this can circumvent the WC2 soft-lock. It will take me a long time to test unfortunately.

Edit: The ESW saves running time, but still soft-locks if used for OP #2. We will need to use a Fire Gem / Disguise door strat to walk back manually.

don't know if anyone's ran into this. I've tested the route on console v1.1 up to moon mountain pass and it doesn't load the map after the wind tunnel. It fixes if I save quit, but I'm wondering if I'm doing something wrong. I've gone up to this point twice and it's done it both times.

@JubJub62JubJub62 yeah I ran into this when I was testing the route yesterday as well. I'm assuming that you also got the glitch where the cutscene with the Earthwalker didn't play until 19 seconds later. The reason why the game doesn't load any other map besides TH seems to be because the game still thinks we're still in orbit when we perform an ESW.

Edit: Looks like Dark-X-Rane beat me to it. Here's some additional info:

When returning to ThornTail, if Fox spawns inside the ship, that means ThornTail is in a buggy state.
- Do not Save/Quit immediately when this happens, or you will return to Orbit. Wait until you hit a checkpoint.
- After getting SS1, the Beacon cutscene will play after 19s. It seems impossible to avoid the cutscene, even with Save/Quits. The best you can do with this time is to get 1x Flame Weed.
- Both LFV and MM Pass will not load properly. I don't think the LFV one is an issue for our current route. I haven't checked SnowHorn wastes, but that's not in route either.

yeah. I got the same thing with that cutscene. bummer tho.

I think we're about to re-route this anyways due to the ESW discovery and WC2 soft-lock. Sorry for giving everyone a bad route, I should have tested it all the way to Andross.

Interesting behavior, when ESWing from another planet to ThornTail, the game will still play an Arwing cutscene:

Edit: More glitches. I'll keep updating this post.

ThornTail Under Attack event needs to be triggered properly, or completing it will do nothing:

If you ESW after getting K4, another ThornTail Under Attack event gets triggered. Completing it does nothing. Probably best to just turn in K4 and ignore it.

Sadly it seems that the ThornTail Hallow ESW still causes a soft-lock on WC #2

However, I still think the route can save time with the ThornTail ESW.

Is the queen earthwalker near the exit of TH toward LFV/CC? Maybe the cutscene is waiting there to start WC2?