Very good game. Really enjoyed it. Though, the meteor strike should not be launchable when the game is on pause: it takes time to launch it without pause mode, but when on pause it does not. Otherwise, the concept is very good and I reckon you should go further and implementing new things. The game might need a balance, since symbiosis with high level trees is sometimes worse than massing new trees around the enemy.
 "Symbiosis"){kind=icon}