I think this challenge is going to finished rather quickly.
The challenge won't end, even if all Gods are defeated.
Whatever happens, it will last for 1 week so that everybody has a chance to fight them.
The actual goal of this first test was:
1. to have fun fighting them
2. to find a good balance of the environment effects to make the Gods just "hard enough"
If after a few days it appears that the challenge is too easy, I'll do what I can to make the next challenge harder.