Glad you were enjoying it before it decided to go silly on you x3 Unfortunately, I'm not really sure why it would do that >.< I know there are sometimes UI layout issues if a player is playing in a different resolution to what I've designed the UI in cos for some reason, the UI scaling sometimes goes really weird! Which is one of the reasons I lock resolution to 1920x1080 16:9 in the build settings. Somehow though, that doesn't seem to make a different when it comes to windowed mode and resizing windows >.< The UI is supposed to scale with whatever the player has for their screen, but even in testing, I find it rarely displays correctly and I have no idea why :( So frustratingly, it's probably not something I'm going to be able to fix >.<
I might still be able to help somewhat though to get it back to how it was in the first place! At least I really hope I can.
I know you said you deleted the game and stuff and redownloaded it, then found that your save was still there and it was still all messed up. That could potentially be because of where some of the files end up hidden on a PC! Again, I'm not a techy person, so I don't really know why this happens, but I wound up having to look into why saves don't disappear while testing games in the past, and people said it's because just deleting the game .exe and folder doesn't actually delete the data. You have to go searching for that in a different place >.<
I can't say for sure, but whenever I download Unity games (same goes for the ones I've made) by default, the data seems to go under:
C:\Users\(your username)\AppData\LocalLow\MelancholyMarionette\LimboLine\NaninovelData\Saves
The appdata folder is hidden by default I think though, so you'd have to go into your folder and file settings and tick the box to enable hidden folders to show up. You can just delete the whole Limbo Line folder to completely get rid of save data and start from scratch. Then whenever you restart the game, it'll just generate a brand new folder.
But trying the potato version might be an easier way of starting over because it should technically register as a different game on your PC to the normal version, and so it shouldn't recognise any save data from the normal version, and it should allow you to start from scratch without having to go hunting down that pesky hidden folder and deleting it!
Sorry I can't be of more actual help though >.< It's always next to impossible for me to fix bugs if I can't recreate them on my PC since I'm a solo dev that isn't even an actual coder, and only have 1 PC and 1 really crap laptop to test stuff on x3 And thank you for checking out the game + attempting to persist with it even though it went crazy on you! :3