Very cool concept. I love territory capture games and this seems like a unique take on the formula. When I played, I couldn't figure out how to penetrate their defences once their root node was occluded by branches.
Feels like a strange mix between Tron, Go, and Chess.
I hope you develop it further.
(And make single player the default setting. Couch coop is cool and everything, but I'm guessing there's way more single players.)