Action Vault have posted part 4 of their Will Rock Q&A, in which 7 of Will Rocks developers answer the question, what is their preferred multiplayer mode in Will Rock and why:
I like co-op. I am not sure if I like it the most because it was by far the most difficult to code or because of the satisfaction I get of sitting around with my buddies blasting away the beasts of Ancient Greece. Not enough games do co-op and I think it is really a fan favorite. It is definitely a lot of fun. The tactics in co-op are pretty similar to multiplayer, with the advantage that you can save a friend or two with your sharp shooting.