Cool tower defense!
A shame that there are no prices displayed for plant upgrades so I personally ended up spam-clicking upgrade in hopes of having enough purple thingy for the purchase. Speaking of plant upgrades: they are interesting, but I don't really see any use of them besides the ones that give regeneration and ability to shoot. As for root upgrade I think it should be the last one considering how much flexibility it gives (but its soooo cool, never have I seen a tower defense where you can chain the tower to your back xd)
The game is very confusing at the beginning tho, would be good to let the player read the introduction in peace before spawning monsters. Also music doesn't loop and just ends at some point which is sad.