If Im not mistaken…(I may very well be, i havent gotten all 9 endings) do you not get a special screen if you unlock all the possible endings/characters. I mean it would be just as easy to just send a screenie (and/or a list of the 9 alts??) to prove your stuff. Id be okay with a send stuff to mod when you get 9 endings or something. Theres some amount of checking to do but hey theres always the banhammer if you waste time with a false claim. If you implement something kind of simple as that. I dunno just spitballing here and if that screenshot isnt there than this idea is a moot point.

Carry on with your argument