Great Games Are...
So someone linked me to Kotaku, and, still not having gotten out of the habit of clicking on Kotaku-related things (and it's hard when you find yourself respecting/liking most of Kotaku's staff), I clicked through. Totilo had written a really cool article on what makes a great game, which was basically "good games provide interesting choices," but I think we can take it a step further than that. If it were simply about presenting the player with interesting choices, then Bioware would make good, even great games--but we all know that's not true, because Bioware doesn't follow through with those choices. There are few, if any, consequences, so the choices are meaningless, even if they appear interesting at first.
Great games, I think, respect the player.
Designers can (and should) do whatever they want so long as they respect their players. Treat players like idiots, as recent Bioware games do, and you've made a bad game. Fail to respect their time, by forcing them to grind (as in an MMO), making them watch really bad cutscenes (as in Max Payne 3), or by forcing them to spend the bulk of their time not playing the game (as in Max Payne 3 again), and you've made a bad game.
Far Cry 2 respects my ability to play how I want. Max Payne 2 respects my desire to feel like a John Woo protagonist. STALKER and Super Meat Boy respect my skill as a gamer. System Shock 2 and Marathon: Infinity may be the only video games I've ever played that actually respect my intelligence as someone who consumes works of fiction.
It's all about respect.
Screw that up and you might as well just not bother.