Mostly, I’m not a big fan of co-operative games. Games suffer terribly without the unpredictability and skill of human opposition, and the whole genre sometimes looks like a collection of semi-functional attempts to solve this big, blaring problem.
But there are a very few that make my grade. And I’ve noticed they tend to have certain things in common: they allow plenty of scope of individual player decision making in the face of the group, offer some sort of simple AI-like mechanics that make it look like the game is reacting to your decisions and have a deep well of variety to add to the narrative and keep things unpredictable.
But the most important quality of all is balancing the need for transparent mechanics that allow for strategic decisions with a strong wind of chance to make sure the game doesn’t become a mere logic puzzle. Lean too far in the former direction and you might as well be solving co-operative Su-doku with your friends. Too far in the latter and you might as well co-operatively shoot craps. It’s a hard, hard proportion to get right and none of the co-ops I’ve played so far, even my favourites, have quite got it right. Until I played Robinson Crusoe.