I haven't watched this yet, but do you know that you can get holy water + triple shot in level one? I remember back in the day when I was planning a Grant TAS, I got through the first level ~2 seconds faster (I don't know for sure, because I was comparing to a Famtasia run) with Holy Water + triple shot abuse on the first boss. The only hangup was one part that looks something like this:
gremlin
-------
gremlin
---------
Trevor
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It's in the room right before the boss and after the room with all the zombies (two screens after the bridges that flip when you jump on them + medusa heads)
When I got to that screen, I couldn't find an effective way to pass the second gremlin without just stopping and whipping, but even with that delay I beat the level ~2 seconds faster. Maybe I should download FCEUltra and whip up a test movie to show you...