tl;dr: topic for 100% routing ideas for timing purposes. Some ideas that did and did not work below.

So, Mariobatalijr and I have been trying to figure out new routes for 100% to make it faster. Thanks to some efforts, Mario was able to get an amazing time (18:37), but we both think it can be improved even more. Mario has been tossing ideas at me recently, so I figured I'd time some of these ideas. I'm hoping to use this thread to come up with new ideas as a community and test them out for viability. This is a better idea than the guide I tried making that kinda fails on the feed back and idea creating that is needed for finding new routes and trying new ideas.

First off, the two big changes that Mario uses in that 18:37 run are the Forever room death warp and falling from Eden Maw.
The first, proposed by Mariobatalijr, saves roughly 18 seconds total, with timing taking into consideration all time spent on those screens, amount of time to get across the map, and the time spent getting the Don't Go Left screen.
The second, proposed by myself, saves 15 seconds (mostly due to walking back to that area) but requires the player to do Spike Entry. In attempts of this route, Spike Entry can be gotten within 3 tries, with failed attempts losing 3-6 seconds. Timing takes into consideration time to walk back vs falling, as well as time to do Spike Entry vs Leap of Faith.

Today, I tested out an idea Mario had for getting 4 of the 5 bags below Green Man immediately after getting Spring Boots, and death warping after getting the 5th up to "Which Way". In testing, I found it to be slower by 1-7 seconds, even with some mistakes on the current route. This timing factored in the time to complete all given screens in the area. This timing did not factor in time spent avoiding bells on the second pass through Green Man.

While the idea above didn't work, I thought, "What if you dodge all the bells on second pass and death warp on the spider back up to the surface?" Trying that showed that death warping back to "Which Way" would save roughly 5-8 seconds (the time to jump back to the portal - the time difference on a small route change).
The player, when going to Green Man for the second time, would get the bell on "Which Way" and avoid all other bells. While, this is possible, there are two bells that can cause trouble on Aqueous Humor and Forgotten Tunnels. Instead of going into Forgotten Tunnels from the top, the player would have to go through the Green Man screen and enter through the right. Then, they would have to jump over the bell at the bottom of Forgotten Tunnels twice in a row to get that bag.
Hitting a bell at any time wouldn't be too bad as you can default to the old route and go through the portal (which would take 10 seconds). Hitting the bell on Forgotten Tunnels after going around would waste an additional 2 seconds spent entering from the right rather than the top.

If you have any other routing ideas, please feel free to post them here. I can get around to timing them eventually, but feel free to time them yourself as well. The biggest time saves will be ones the involve bell death warping or that skip long segments of walking.

Found a 5 second time save.
Get the bell on "Before the Crash"
Don't get the bell on "Hold On Tight And Don't Look Down"
Don't get the bell on "The Coin And The Courage"
Get the money bag and then death warp back to "Before the Crash"

Main difficulty with this one is the timing on Don't Look Down since the window for falling is much smaller when avoiding the bell. Missing even once would lose all the time gained from this death warp, so not advisable in races.

It's pretty cool you guys are finding this stuff, I knew my route definitely could have been improved further but I never thought up a way of doing it. Good work. c:

Mario came up with a slightly faster variation on the Before the Crash death warp. Instead of dw to Before the Crash, dw to Don't Look Down bell and jump up the side. It's possibly slightly faster to jump up the wall than jump across that screen. Also makes any deaths waste less time.

Getting the bags on Vestibule and the bottom of Attic Storeroom is faster after getting the bag on Great Hall before exiting that area instead of getting them when entering by 5 seconds. After getting the bag on Great Hall, jump across the platforms without falling, jump up and get the Attic Storeroom bag, then jump down to get the Vestibule bag and exit the area. Then, get the Worth It? area when getting the Spider Gloves after losing. Slightly more difficult but, like I said, much faster.

Mario keeps the strat train going! So, in Attic Storeroom, you can drop down from the upper ledge and land on the edge of the spike ledge (similar to the beginner strat for Leap of Faith). From there, you can double jump down to the lower bag. Using this, it is possible to get both Attic Storeroom bags and the Vestibule bag all in a row right before leaving the area. That just leaves the Great Hall bag. However, it only takes 1-2 seconds more to go get that bag when first entering the area (vs just going straight to Hollow King Transformed). Like the previous strategy, Worth It? is gone to when revisiting the area after losing. In total, this saves an additional 4 seconds over the strat I posted 6 days ago, bringing that area to a total of 9 seconds faster than previous routes. Thanks Mario!

no problem ZZKer, imma try my best to keep the strat train going for a long time, and there are MANY more things I can find/improve on. 😊
~Mario