An awful lot of games ship with a Co-Operative mode of some sort nowadays, but Perfect Dark was one of the very few that also included an interesting twist on the concept called "Counter-Operative." Before we get into that, I'll go over some of the broad strokes of what constitutes Co-Operative gameplay.

Co-Operative gameplay in video games of nearly any genre will at least involve special missions or scenarios. Grand Theft Auto: San Andreas had a few Rampage missions that were restricted to two players only, as an example. Super Mario Galaxy had Co-Star Mode, which allowed the second player to help out with enemies and pick up Star Bits.

Some games will have challenge maps or alternate gameplay modes. The Gears of War titles had Horde Mode, which allowed players to cooperatively fight against wave after wave of enemies. Wave-based "Horde Mode" is practically a gameplay mode unto itself these days, and Gears of War likely had a lot to do with it sticking around.

There is also, of course, straight-up multiplayer games that allow players to join teams. Any sort of "Blue Team" vs. "Red Team" scenario could be argued to be a Co-Operative experience whether it's in a first person shooter, real time strategy, or something else.

Some games go a step further and allow players to play some of a game's campaign (or even the entire campaign) with a second player at their side. The Saints Row games have had Co-Op in them for some time now, and some of the most entertaining videos in my experience tend to be the Co-Operative experiences.

So, we have a firm establishment of what "Co-Operative" is. So what's "Counter-Operative"? Perfect Dark does indeed have a standard "play through the campaign with two players" Co-Operative play, but Counter-Operative turns that on its head and makes Player 2 the enemy. The second player is randomly assigned control of one of the existing enemy NPCs. AI wasn't amazing in the Nintendo 64 era, but even the AI of today can't match up with a human player unless it blatantly cheats.

What does it add to the game? Well, it adds a competitive experience to what would otherwise be a non-competitive endeavor. In Perfect Dark, the NPCs are all in the same place and generally behave the same way. When one of them can be freely moved by a human, you might soon find yourself being ambushed in what you thought was a safe area.

Most game campaigns simply involve running through a level or section of the overworld and completing objectives. Some can be rightly challenging, but the additional (optional) experience can add an awful lot of replay value to the game. You can run through a level with a Co-Operative ally ten times and have essentially the same experience many times. Ten Counter-Operative experiences on the same level will likely be different every time as both players will be adapting their strategies.

For the purposes of this article, the working definition of "Counter-Operative" we've established is "Player 2 opposing Player 1 in what would otherwise be a single-player experience for Player 1."

Counter-Operative play would be a neat additional feature in games, especially those that think it's a good idea to include Co-op play. However, the concept of "Counter-Operative" play need not be an option. The Dark Souls games have "Invasions," where you can be attacked by another player who loads into your world. Most of the time you'll be dealing with enemies & bosses, praising the sun, and cracking skulls with your main gal Felicia. However, if you happen to find yourself in a vulnerable, area you might have to deal with an enemy much smarter (or much dumber, perchance) than the cleverest AI and that can be a real game-changer.

Party Hard is another such example. The game has Twitch integration, which allows viewers of your stream to throw a proverbial wrench into the works and make the level that much more difficult. Perhaps they might vote for a pizza to be delivered, or perhaps they might vote for a SWAT team to show up. Party Hard makes your entire Twitch chat acting as Counter-Operative to your gameplay experience. Well, more than they usually are, anyway.

Perfect Dark was probably not the first title to allow someone else to mess with your game. I wouldn't be surprised if there were another example of the concept in the decades of gaming preceding one of Rare's finest titles. To my mind, Perfect Dark was the first widely popular game to put the concept to good use and it was certainly the first one that I saw.

Counter-Operative gameplay can add replay value to essentially any game, and I would argue the human factor makes for something an order of magnitude more complex and rewarding than just Co-Operative play. I hope that in the coming years we will see gaming companies pick up on the concept of Counter-Operative play as they have with Co-Operative play.

What do you think of the idea of Counter-Operative play? Are there any games you can think of that would really benefit from having a Counter-Operative mode? What games had Counter-Operative play that worked really well? Let us know in the comments below!