Looks good, the gameplay is fun, a bit too slow (maybe add an 1.5x, 2x even a 3x speed button)
The rocket launcher if planted in large amounts all at once is targeting the same enemy even if just a couple of rockets would kill it, wasting rockets in the process (I suggest randomizing the wait cooldown of plants by -10% to +10% every time they shoot so they don't attack all at once)
Good game though, keep it up!