The farming mechanic is a really interesting wrinkle on an already solid top down shooter. At first I thought it would be superfluous- why bother farming for heals when you could instead focus only on dodging and shooting and not need heals; but the steady health drain is a very elegant solution. Getting highscores involves both tight dodging but also intentional rotation around the map to maximize plant output to keep the run going as long as possible. It's neat!