I went through previous runs of this game, and it seems like there was no clear place to start the run/timer. Judging from previously submitted runs, I think starting the timer when you skip the first cutscene (or when the "Stage 1-1" screen starts to appear) can help make things more accurate.

If anyone has feedback about this, just let me know. I only had to change a couple of times but the rest of the runs skip the cutscene immediately after choosing "START" anyway.

Have you tried holding SELECT before choosing START? ;D

@Nobleboy77 I have not; I usually press it after hitting Start lol. But that's good to know if anyone sees this!