Low friction co-op games are an underserved market, but none of these games are for me. I'd be a user if it was a challenging co-op tower defense or bullet hell game, even if the graphics were bad.
Yeah, but those games are not free place, wc3 tower defense were like: here is your grid, go wild! The coop part was where the grids met or you pushed the monsters with a labyrinth from one side to another.