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.

I've looked for a way to do this early before but I thought the catacombs don't load until the last time around town, at what part of the game is this in?

I know for sure this works before and after fighting Scarlet. Not sure any other time.

A bit late to the party here, but I can confirm that the underground areas do not load early in the game, but they are fully loaded to drop down to after the Hell Descent/Scarlet boss fight.

And thanks yet again for the shoutout Starwin! <3