The last castle was a very unique and fun game. I still hope it gets a rebirth or sequel.
Imagine a tower defense game, where you control one hero as (auto shooting) "tower". You only control the position and the special skills, but this you did in a team of two, chosen from the classes mage, warrior, archer. You could also lvl up. It needed two really smart players to win, so that was rare if you didn't come with the right wingman.
The castle was in the middle and monsters came from two sides. Typically each one took one side, but one had to help regularly and communicate that.