Recent messing around has led me to discover this new clip for All Bosses NG/NG+.
After beating Scarlet and entering the Town Hall you can skip using the key, watching the Ceremonial Dagger cut scene, and traversing the maze.
This will save around 1:30 when done quick enough.
Thanks again to NeuroticNinett for the inspiration to test different areas out.
Whelp time to finally post some new tech!
Recently I was contacted by NeuroticNinett who had the idea of clipping through gate 4 of the sewer to skip majority of the level. Thanks to her guidance I was able to learn the setup she came up with, and as of right now I've been able to improve on the concept making these clips 100% viable in All Bosses NG+ runs.
Not sure if this is viable in All Bosses NG since you're missing out on ammo drops, but I'm not too sure.
These setups consist of doing two clips to get through Gate 4. The first one I'm still figuring out a consistent setup to get in the wall as quick as possible, but right now I'm letting the wall just bounce me around until it pushes me in. The second clip however I have three different setups.
Shotgun Method
Pistol Method
Shotgun Method 2