Usaco's grenades are very powerful and can clear enemies faster than any attack in the game. The LVL 2 grenades might even be better than the shot gun because of the splash and distance you can use them, so future runs might optimize avoiding shotgun upgrade until you are near the boss.

One issue I struggled with in failed segments not included in this run, was getting used to Usaco's Metal Gear jumps. It takes her a few frames to turn when she jumps to aim your special which caused me to waste a lot of SP because she did not turn quickly enough.

Getting quick KO on worm is possible IF he uses his slime as the second attack and another harpy spawns for SP restoration. Waiting for this instead of rushing him into the ground when he loses half his health could save some seconds. We lost some time when we ran out of SP.

In prior segments, I struggled with skipping the Save the Queen against Queen Bee. I either ran out of SP to stop her or a drone stabbed me in the back. Then I utilized crouch fire at the beginning of the fight until the drone was prepared to stab me. This does the extra damage necessary to finish her with your shotgun, but you 100% need to arrive at her with full SP. This can be complicated in the final room before the Queen Bee if you take the bonus route.

I made some mistakes so there is room for improvement.