I had a most wonderful experience playing Portal 2 last week. Valve has always been at the forefront of user experience in games and the lessons they've learned are highly apparent in this title. I've been yelling at everyone who hasn't played it yet to play it immediately and I'd be inconsistent if I didn't do it here, too, so PLAY PORTAL 2 RIGHT NOW HOLY CRAP
With that out of the way I'd like to talk specifically about Portal 2's co-operative mode, because it is neat. Unlike other co-operative games such as Left 4 Dead or Civilization (which is co-operative when you want it to be), Portal 2 is fundamentally a puzzle game. It's not about who can jump the highest or push around the most blocks, it's about solving the puzzle at hand and moving on.
So how does a highly competitive person (like me) derive enjoyment from it? I'm glad you asked. Luckily, you and your co-op partner can still be horribly injured in this game, leading to the best sort of competition of all: griefing.
As two friends who have played a lot of video games together, my Portal 2 co-op partner and I are no strangers to hindering each other for comic effect. If we're about to beat a level, but I can see an opportunity to kill my friend, you'd better believe I'm going to take it, even if it means I'll have to spend a few minutes getting back to where I was. He'd do the same to me. It's all in good fun and we know we're doing it for the roffles (read: sadism) so there's no hard feelings.
Now, Portal 2's co-op campaign has hundreds of opportunities to kill the other player. Just for starters, there is a bridge that you can turn on and off, and standing on this bridge is necessary for crossing a giant chasm of acid. You don't really need to think very hard about this to realize that when one person is on the bridge, the most natural and normal thing to do is to remove the bridge. Even better: stand on the bridge, too, so your partner thinks you're not going to remove it. Don't let your own death stop you from killing your Portal 2 buddies.
Add to that the lasers, anti-gravity funnels, bottomless pits, giant spikes and holes in space time and you've got yourself a toolkit for both solving both the puzzle that the level represents, and the puzzle of how to lure your partner to his death without his knowledge. Portal 2 is as much about getting through the game as it is about fucking around with your friends.
But the neat thing about it is how those two factors balance. When he and I started playing, killing each other was the top priority. We made it our business to see who could figure out the map first, take charge and direct the other to his death under the guise of solving the puzzle. For both of us this is just how co-operative video games are played.
Four or so hours later when we were done, I realized that by the end of campaign we had completely ceased our hostilities toward each other and had focused solely on beating the game.
This, to me, is amazing. My friend and I are the kinds of people who would make and subsequently use GBDB. We revel in doing things the game itself does not want us to do. For us, to play the game first and foremost for the game itself is an oddity. The fact is, Valve designed this game to be compelling to the point that even people like us would be drawn into it and would rather advance the plot than stab each other in the back. And I'm not entirely sure how they did it, either.
The first few co-op levels are simple: they're there to show you the ropes, to get both players to understand the basics of the tools they will be using throughout the rest of the game. At that point, some of the levels are specifically designed so that you can exact a good-natured murder upon your partner. These levels are easy to figure out and contain obvious areas for messing your cohort up.
I think that Valve anticipated that people would delight in deliberately disintegrating dear deputies to at least some degree and built early levels to take full advantage of this to get all of that friendly animosity out of the way before bringing in the truly compelling levels later on. Because by the end, when my friend and I had spent almost 15 minutes trying to figure out one puzzle, we did not once kill each other even though we were frustrated from having a hard time finding the solution.
Thank you, Valve, for teaching me something about how to derive enjoyment from video games. Once again you have done a wonderful job.