Thanks for trying out our game! I'm glad you were able to find a way to play, though keeping the other player alive sounds very difficult :)
In fact, the original concept for this game was a single player or co-op wave based game. After playtesting with two players we realized we had a lot more fun making it competitive and so that became our focus. Sadly there is a bool that toggles single and multiplayer, but we overlooked that before the submission deadline and did not expose that option on the main menu. It's something that would be easy to add if we decide to update the build.
Another idea that I had a day after submissions was to actually have a simple AI for the second player. It would incorporate the same pathfinding that the enemies currently use, and have simple triggers for the attacks. Potentially something else we could add as well.