The game is stupidly difficult. The first whack of levels are okay so you get into the game and feel like it's beatable, but then they make it impossible so you'll spend real money for an edge. I'm at the point where there isn't a single available map that I can beat, and I can crush the first game in my sleep.
Shit like, "You can have no more than 12 plants in play at one time and you can't spend more than 2000 total sun." Fuck you.