I probably know what you are thinking. Let me try to guess. It's probably the first online multiplayer video game. It's most likely on a computer of some sort. It was either on disc, disk, or placed in an obscure place making it hard for people to find. Am I close? To answer those: no, no, and no. And this game might be closer than you realize.
Long story short my nephew and I decided to play a game together. The problem was that he wanted to play split a screen on XBOX. I wanted to spend time anything but XBOX. We drug out the 5200 and tried a bit of Dig Dug. He said he wanted to play a game with me at the same time, not taking turns. The 5200 really lacks in that department as most of it's games pit each other one on one for the highest score. The only two games I had that I knew 2 players simultaneously could play together were Asteroids on the 7800 but that machine was on the injured list. I grabbed Junior, one game, two controllers, and setup the next game we could try.
I remembered playing this game in the past with a friend and the game was setup where we were playing together at the same time. But I couldn't remember the setting. Thank goodness I had the manual. We tried a few game settings, some were weird, some were cool, one in particular made itself really step out.
In modern games the online world is full or gamers playing their favorites with family and or friends in either death match modes or working together towards a single goal known as co-op modes. In the co-op mode the score no longer matters. Two or more players working together in a single game can be more enjoyable than going it alone. It has become a key component in modern day gaming that has helped many game titles become popular and unforgettable.
Game number 33 of Space Invaders easily fits into the co-op mode. While the instructions may claim it to be a competitive setting if both players forget about the score and work together to see just how far they can go Space Invaders 33 is sure to entertain. So, would that place 2600's Space Invaders in the title for.the first co-op video game ever? I'll let you decide.