When different people play the same video game, do they play in similar ways? Do they rely on similar manouevers -- or does each gamer have a unique way of navigating a level? Obviously, since the enemies in a game are programmed to have some artificial intelligence and to respond somewhat uniquely to each player, theoretically there ought to be at least a handful of different ways to play a game. But how varied are our responses?

To find out, the writer R. LeFeuvre performed an intriguing experiment: He took screengrab recordings of 15 people playing the first level of the classic sidescrolling shoot-'em-up Gradius, merged them into a single video, and studied the results. In a fun story called "Averaging Gradius" at The New Gamer, he reports on his findings. An excerpt:

The average time taken to kill the end level boss was 20.055 seconds, with the fastest player finishing him off in a mere 10.01 seconds. Six people finished the boss off at nearly identical moments. It would seem that the boss, bored with the player, actually self-destructs after 27 seconds. Beyond the almost perfectly synchronized explosions, further proof of this self-destruction can be found in the videos: no 10,000 point bonus (given to players when the boss is defeated) was awarded to these six players and, in a few of the runs, the boss detonated when when there wasn't a single bullet near it.

Obviously, Gradius is a pretty tightly constricted game -- the action scrolls relentlessly rightwards, so players have a relatively limited number of things they can do. It'd be really interesting to average out the games played by, say, 100 players the first time they cracked open a more open-ended world like Grand Theft Auto. I suspect that even with an open-ended game, people's behavior would still fall into fairly regular patterns, because of the very nature of games. They're systems composed of rules that set up arbitrary goals; even the most seemingly freeform game will inherently include design elements that coax players into a few common forms of behavior. Without limits, a game isn't a game. As a writer back in the 80s once said -- I'm being intentionally vague because I can't remember who the heck this was -- "it is ironic that a video game is said to be 'mastered' when the player has fully subjugated his behavior to its will."