Big Wave Beach contains 32 levels, it is one of the hardest worlds to complete. It is made especially hard by the tide which comes in and out drowning your plants. The lilypad which is unlocked on the first level in this world will be an essential plant to select for each level of this world, as well as the tangle kelp which is unlocked at level 7.
Here is a rundown of all the plants unlocked in this world and a little bit about them:
Lily Pad - Level 1
Really useful in this world as it will let you plant non-aquatic plants on top of them.
Tangle Kelp - Level 7
Use this one like you would a bomb or chilli plant on dry land. The first zombie that comes across it will be pulled into the water ... never to be seen again...
Bowling Bulb - Level 12
Pretty strong and useful long range plant that can hit zombies in multiple lanes and bounce off zombies to make multiple hits. Probably one of the strongest plants to be unlocked up to this point.
Guacodile - Level 20
Fires low strength seeds at zombies in the same lane, when it is hit though they will zoom forwards and attack all zombies in the same lane. Unfortunately at this point the plant will be gone, and you'll have to plant a new one.
Banana Launcher - Level 28
A true candidate for the best plant in the whole game. This is expensive at 500 sun but it gives you the ability to target any enemy in any lane. The leaf effect is really good too firing multiple random bananas.