Glitches and manipulation are not allowed within 100%. Should more manipulation be found, we will most likely just make a glitch %. For now, we know the following, and it is restricted from runs:

Billboards - RR1 saves named accounts and billboards as physical files. Deleting the named account without deleting the billboards will cause any account created with the same name to draw up the previous billboard files. (i.e. If you name your character Amy, complete billboards, delete the file Amy, then create a new character named Amy, the billboards from the first account named Amy will still remain and the game will consider these complete.)