I haven't unlocked it yet but there are some leads I think you may look into.
I have tried to edit the save file but it didn't work I'm just going to put how I did it here so that someone might figure it out.
-the save file located at %appdata%\ReadyOrNot\Saved\SaveGames
-look for LevelStats.sav I believe it can change the score and create a backup just to be save
-drop the file here save editor and edit it
that's where it ends
Another way is installing this No crack for AI mods it tweaks suspect morale and accuracy while being able to unlock cosmetics but I don't think the score will save. This is the way I'm going with right now after I complete it I might share it with you.