Generally I enjoy this but I HATE those levels where the game chooses the plants and defenses you will use. This is a particular problem in Level 18, where there are not enough spots to place said plants, so you are left with the weakest plants. It is impossible to get past the 15th wave out of 21. I hate to admit it but I have replayed this level so many times that I no longer want to bother with this game.

When you consider that this happens at the EASIEST level, this makes no sense...the creators really screwed up on this one.