Yesterday night I pushed a build of the same version fixing a bug, I exported the game and put it up and went out to take a leak. Game hasn't been openable since, why? The export was corrupted, and no matter how many times I re-exported it remained corrupted... So after some trials and some errors, I got to the bottom of it and fixed it, learned a new thing today. (Game works now btw lol)
Thing I learned today for Godot indie devs or curious minds alike:
If your project.binary's header corrupted, even without changing your engine's version, my way of fixing it was first, finding out about it through GDRE Tools by opening the Abyss Veil.pck file. Then I deleted the .Import file in the game's project so Godot would re-import it all. Then I uninstalled and re-installed Godot's Export Templates. Closed and re-opened the project, exported it.. Compared the 2 .pck files with GDRE Tools, launched the game and it worked!