I think its safe to say that a "Game" is anything that has a factor of randomness and chance, and often features some competitive air.
Poker, Chess, Monopoly, Darts, Baseball, D&D: all get lumped into games.
But this isn't really what I wanted to talk about. What I really want to talk about is Hit Points.
What do Dungeons and Dragons, World of Darkness, GURPS, and Shadowrun all have in common? A health metric.
One of the things that I dearly and truly love about Shadow of Yesterday is how its version of the health metric includes not only "getting hit with pointy things" but also "How'd he talk me into doing this again?" and "I swore I wouldn't fall in love with him.."
See - and maybe this was where my half-baked lead in came from - most game systems, er, Role Playing Game Systems, feature a combat resolution system that is somewhat granular. You whack orcs with a sword until all their hit points spill out, then you collect them in the form of gold and XP, much like a pinata. In D&D, you walk into a room with a bunch of hostile critters and you roll a bunch of dice, and then you win. Its not a single dice roll. But turn the coin over - if you walked into a room with a suave diplomat, who wanted to convince you of the foolishness of your plan to kill the king, it might come down to a dice roll. If your group is even willing to tolerate its course being changed without bloody combat. And that's also assuming that they do not make the aforementioned diplomat into just another fleshy bag of XP. But what I'm getting at is that even among the most open minded D&D groups, diplomacy and such things are relegated to an afterthought, a single dice roll. And back to the beauty of Shadow of Yesterday - if you're going to talk Ungar the barbarian into not going down into the village and slaughtering all of the able bodied men, you get the same kind of method and mechanism for doing so, as you would with combat.
I was trying to think of ways to hack other systems, and include some kind of a metric like this, and no great ones came to mind. For D&D, I imagined having hit points, and will power, side by side. Anyway, I digress.