I haven't actually beaten the tournament yet, certainly not on hard, but I had an idea. If we actually beat the tournament on hard, or maybe even Nightmare, how about this: for the Demigod we win with, we unlock some sort of "God form" of that demigod, basically letting us enter in how much we want to multiply our damage? This would just be for fun, single player only of course, just to let us walk around and totally pwn everything in our path.
Just a thought.