Well it was clear that Betray was the better strategy.

I mean there are 2 options:
-The other guy/gal betrays - then you get nothing if you co-operate. Since you're competing agains him/her you need to Betray
-He or She co-operates - then Betray gives maximum points.

For the future the mechanics need to be tuned a bit. Other than that thanks a lot for hosting this! :)

That's not completely true. If you and your likely other prisoner both can pass the top ranked player by cooperating, then that's the better decision strategy wise, as long as you can negotiate.

What would you suggest?

And then Betraying is still the best strategy, morality aside ;)

Knowing you partner, as was suggested, might be an option.

Have maybe 2 games as prizes. So that co-operation to pass the people before you is a real incentive. Maybe one 9.99 and one 5.99 to make it interesting.

Partners decided more or less randomly so there's always a chance you'll meet someone again, so Betraying would have possible consequences. 2x co-operate will be more valuable then a quick Betray with disregard of future meeting.

Something like that I guess.

Getting points should be rewarded, not just getting MORE of them. This way cooperating will be a lot more likely.
On the other hand - this would require a bigger prize pool... Like $3*# of people*# of turns.

But if you know for sure you'll meet someone again then co-operate will almost always be the best choice in the first round to get more points overall. If it's just a possibility then it's an actual risk when you make your choice. Would be interesting to see either way :D

very good point... so a random draw should it be... but I would say, more rounds than just #Players - 1.

I think some became bored of the game, because they knew really early that they have no chance to win anymore.

I just had an idea to improve the fight on top.
1st price: $9.99 Game
2nd: noting
3rd: $5.99

This would give a nice fight in the top 3, and the players with less points also have a chance to get up to the 3rd, if the 1st is unreachable.

You might even require a certain amount of cooperation.
Instead of breaking out of prison, you could 'steal a GoG'. A team of burglars is at the start and if they lack to at least cooperate x times, they get nothing at all as the mission simply fails.

I think if I was to run a similar game again I would make some changes. I think maybe if you always knew in advance who you were competing against it would add an extra layer of tactics to the game and it might also help if you could face the same person more than once.

Alternative suggestion: $9.99 game for 1st place, $5.99 game for the LAST place, a sort of "consolation prize" for the person who either gets betrayed the most or notoriously fails backstabs ;P.

Like I said, though, it would be best for every point to matter, since with the current system the 2nd place is worth exactly nothing and as such - betrayal is cheap. If a person were to have a choice between getting $5 or both people getting $3 each, antisocial behavior would actually have negative impact on the other person and would be more "greed" than simply "trying to win".
Also - assuming our community is nice and altruistic (and the above "every point matters" system), we could provide an additional incentive for betrayal by making it anonymous and only announcing how many people chose to betray each round. While the total gain would still favor cooperation by everyone, it would take one rotten apple to upset the entire system, threatening to collapse into 0 points for everyone.

A slight alteration of every-point-matters could also be interesting: making it so that every 6 points (two cooperations) can be spent on a $5.99 game and every 10 points (two betrayals) on a $9.99 one. Of course - we'd still need quite a bit of contributors to get enough funds for this but that's one of the reasons it would be so exciting to watch (and play) ;P.
So, for 6 people with 5 rounds we'd need $90 (or $72, using the "slight alteration") (although the most hilarious scenario would be no one winning anything >:3)... which would mean each person ending up with 15 points, 1 point away from 1 $9.99 game and 1 $5.99 game (although this point could easily be gained if that person chose to give in and betray "just this once" ;P).