Thanks for playing! If I remember correctly it should be about 0.1-0.2 seconds or something like that(?), the same thing as Hi-Fi rush in normal difficulty (and the bare minimum I needed to make sure you can't just mash a button and get everything right). I don't necessarily intend to keep it that way though, the fact that this game actively penalizes you for getting your timings wrong means that a bit of the challenge in that regard should be lifted away from that particular aspect of the game and shifted towards meter management or something along those lines. We'll have to iterate on this with time and find the right balance here, along with some difficulty options that straight up let you choose between different timing windows.
I didn't observe many issues with regards to timing when my friends were playtesting the timing windows, but I do know for certain that the experience won't be the exact same between people depending on their hardware (i.e., monitor input delay or audio device).
Right now, you can kind of get less input latency by switching off vsync in the game settings and maybe perhaps changing the anti aliasing method to FXAA or something (and also maybe by messing around with your GPU settings, the same typical tricks people do for other rhythm games), but the correct way to solve this issue is to introduce a latency calibration screen into the actual game so it can compensate for it (which is what most rhythm games do nowadays). I intend to work this into the game as soon as I'm able to update it, we kind of just ran out of time and couldn't add that feature for this jam.
I'm glad you liked the visuals!