I would really love to see a full-game completion category (100%), but it's unlikely that anyone else would attempt it besides me. So, how about adding a category like this:

All Char: Complete the game with all characters.

5-10 Char: Complete the game with 5-10 characters.

I hope this sparks greater interest in the game :)

And perhaps it would make sense to add a category for co-op runs as well