Pac Man has a perfect score. It is possible to attain 3,333,360 points from maximising power pellets so that all four ghosts are eaten, plus all fruit is consumed on each stage on top of the dots. In doing so, the kill screen is reached (due to an overflow) and game play ceases. That’s it, you’ve accrued the largest amount of points possible in Pac Man.
In a game designed for repeated play, it can be important to introduce an element of variability to the scoring mechanisms. In my own game, SLaVE, I shall be working out such kinks with the scoring. For example, each enemy giving a flat point-bonus would mean that players who beat eight stages (as an example) would all beat those stages with identical scores. One such way I have changed this is a “PERFECT!” bonus for defeating a level unscathed.
I am personally a fan of the myriad ways a game can further reward a player past the basic points value of enemies and/or collectibles. SLaVE will feature a time bonus for quick completion of levels (coupled with a double-damage mechanism for low health, to introduce a risk/reward element to the proceedings).
There are, of course, other ways I am not considering at this time — I have always favoured combo-scoring systems in score-attack games, and it would be nice to include one. But SLaVE is not a game well-suited to this. A future game, perhaps. But I think that a game in which a ‘perfect’ score is possible (and thus placing a cap on a player’s mastery of it) is, ironically, inherently flawed.