Did you want to add a restriction on having any individual game appear more than once? If I listed Katamari Damacy for all 25 slots, I'd assume that you wouldn't go ahead and give it 325 points.
Any similar restrictions on listing a game more than once under different versions/editions? I'd figure you wouldn't want someone listing Resident Evil 4 on one line and Resident Evil 4 Premium Edition on another.
Not trying to be a dick. Just want to illustrate a few possibilities that aren't addressed at the time of my posting this.
I'll come back to this during a weekend when I can look at my collection and judge.