We have completed a number of games, each with between 1000 and 3000 rounds. We are currently in the process of contacting those who will be interviewed, verifying our results, etc. While we do so, we thought the community might like to see some of the aggregate results about how the game turned out.
The below graph shows the number of surviving players vs. round for some of our games. Initially, there were 350 good submissions (submissions that had the right syntax, did not freeze or break, had the appropriately defined classes etc.). As you can see, the initial food bank keeps everyone alive for a while and then quite a few people start to die very quickly. Eventually a new population equilibrium composed of survivors is reached, which is where the tails flatten out. Since this equilibrium is stable that's an indication that there are enough semi-hunting algorithms to offset the continual food loss of the population. This is good: you Brilliant members have given us reason to believe that there is hope for the human race, as not only are you smart, but apparently you are not all mean slackers too.
Who did survive all the games? Below is a graph of the reputation vs. round death. In other words, when a player died we recorded the round of death and the player's reputation at death. As you can see, those who hunted all the time died very quickly. However, those who slacked all the time did as well. This was by design - we hoped that people would realize that there were strategies that beat the always slack strategy and many people did pick up on this fact. Hence the players who lasted the longest but still died did actually cooperate some.
Additionally, the end-of-game reputations of those who survived every game are plotted below (remember every game ends after a certain randomized number of rounds). As you can see, the survivors had reputations clustered around 0.5, in fact the survivor reputation average worked out to be 0.54. I'm curious about the possible spike near the reputation of 0.2. My suspicion is that these slacking players built up a big buffer of food in the early game, but after most of the other algorithms died out these mostly slackers were slowly starved out by the remaining players. I have not explored this yet, however.