Damn good job
1. Oh ok that's a bug with the failsafe I have for if the hold note score is above what was pre-calculated to be possible. That can still happen even though the hold notes are consistent, just because of the inherent imprecision of floats. It'll be fixed in 1.7.
2. It's more of an "all notes hit" instead of a "full combo" check, idk if I'll change that.
3. Latency offset and the desync mitigation system do both do the same thing (adjusting the timing by moving the note spawn point), but they solve 2 different problems.
Latency offset is for the player to be able to correct for general (mostly consistent) system latency. So for example if someone is using bluetooth headphones, they'll often have a lot of very noticeable latency, making rhythm games pretty much unplayable by default. The latency offset lets them adjust that, so that it syncs up (they'll probably need to turn off the hit sounds though). Most rhythm games have something like this for the player to adjust.
However the desync mitigation system solves for dynamic desync that just happens due to slight timing irregularities between the audio and the midi player. This changes over the course of the map, so the offset is adjusted over the course of a map. Although like I've said, this system will be removed in the next update since I moved to using my own custom note spawner that's directly tied to the audio's time, instead of the midi player's own internal timer.
5. Oops, yeah I think I just forgot to reimplement that when I did the hold note revamp. Surprised I didn't notice that considering how much I've played, I guess it's just because I've mostly just been playing my maps that do give plenty of space between then end of a hold note and the next note. It'll be added back in 1.7.
6. I'll maybe look into that, won't be 1.7 though since it might take me a bit to get working, and I really need to stop adding features to this update or it's never gonna come out lmao.
7/8. I do want to do a revamp of the settings menu, give it tabs or something, but yeah won't be this update, same reason as 6. I might add a txt only setting. For now for custom maps, you can just go into the txt and remove the "ColorKrisL, ColorKrisR and ColorKrisBox" lines.