Reviewing every PVZ1 and 2 world: Roof
This world is probably just under Pool in terms of fun factor, since it's also fun but has a much more annoying mechanic. First of all, you can't even use the Pool plants here because of the lack of water. Second, the roof slant makes it so you need the Pult bros, and if you wanna use Kernel-pult, you're gonna need a Cabbage-pult to back him up since he has Pult firerate but Peashooter damage with kernels. Finally, the flower pots are required to plant more than three to five columns of plants on the roof, and you have to have them to use most of your attacking plants. That bumps it down severely to 4/10.