M2 has been sitting on the back burners un-played due to the lack of co-op. Honestly, I would even be willing to buy an upgrade if it came with this functionality.
I found the single player missions very fun, but as others have stated they get very easy after about the 2-3 mission once you figure out how to spam the enemy. At first, I was under the impression that kingmaker was going to have MP co-op support, but that appears to not be the case.
As others have pleaded please consider adding co-op. I understand that the current implementation may very well be based on some type of scripting system, but there must be a way to add random generation features for humanoid AI similar to normal AI. At least for some co-op potential.
Each level of hardness would generate x + (rand) # of towers, guilds, buildings, etc on the AI side. If the AI could attack us even better, but I don't even remember seeing the AI humanoids attacking me in the SP maps.. so that may be out.
Great work on the game though!