My capture card lags from my splits, so I split a bit early at the beginning, but I also split early at the end, so it should even out. Also right after beating the boss I quit to the menu to skip the ending cutscene, which kind of feels like twisting the rules to gain an advantage, but I think it's the fault of the rules being too vague.

Mod note: Adjusted rules to be clearer. This means the run is now shorter (and also more reset-friendly). Technically, if you quit during the cutscene in any%, you would not get a star.