So after playing a ton and trying to find the best routes there are a few places that stick out as sore spots:

1-1, the pack of enemies with the helicopter. Attacking on the ground costs time, but I haven't found a reliable way to skip this pack. Damage boosting doesn't seem to be a time save here either.

3-2, obviously the water level when you enter the map highly dictates your route. Finding a way to force the water level or manipulate it somehow would be awesome.

Kitchen boss, should be beatable in 3 cycles as long as you get the pot to go to the opposite side wall first. I've put on the infinite lives code and fought this boss over 100 times but haven't figure out a way to force it. Not sure if it is just random or I'm missing something. Also the frame perfect bug used in TAS runs could move this down to a 3 cycle fight if you can get it reliably.

Attic boss, getting the piece that falls off to always "stick" in the boss when you throw it up is the biggest time saver. I've found that always walking to the right of the boss before throwing it seems to help, but not sure if there is an exact science to it yet.

I think its possible to get the sum of best segments below 15:00, and I would love to get my single segment run to 15:20.

Anyway, if anyone has any other thoughts feel free to post them.