Alright, if you're going to split hairs, then I guess I'm going to have to get more specific about it. You can't have a negative ratio of finished games to new games unless at least one of finished games or new games itself can be negative. So unless you've found a way to unplay games, I don't think you ever have to worry about a ratio of -9.

Also, I guess more fundamentally, no it isn't. A ratio of +1 only exists when the two quantities are equal. x+1 is definitely not equal to x.