Drain Defense 0.51

Early functional prototype of a fluid based tower defense game v0.51. Avoid letting the vulgar objects down the drain! You have 30 lives, your only objective is to "stabilize" the map, in other words get to the point where you can't lose!

Land! You'll need some if you want to build towers on water.  This game is open to collaboration! Please see https://godotforums.org/d/33142-drain-defense-playable-and-open-to-collaboration.