IIRC last time the winners were programs that had some random element in their code and "got lucky" (in the sense that if the tournament had been run multiple times and the results averaged, they would not have won). So maybe you should guard against this by performing sufficiently many copies of the tournament.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one.
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.