Huh, so now we have five boss skips. I don't think ammo management is a problem anymore. Knew that one enemy looked fishy.
Basically, there's this fish enemy we can spawn. Exonym's previous attempts didn't get this one to move, but I then found we can face left and jump early enough. Our important pixel gets us past the floor tiles, and down low and early enough. Once it's out of the de-spawn zone, it's a matter of delaying it long enough to meet the boss, then kill it. That enemy moves rather quick and will de-spawn off the right side of the screen without the ouch delays.
If anyone's curious, the base movie the savestate came off of was Team 4's run.