Infinite banana bombs:
If you go to the weapons options screen and hitDown, Right, X, Square, Square, X, Square, Square, X, Square, Square you will recieve infinite banana bombs.

New Weapons:
On the 'weapon selection' screen, press X, and then Square. Repeat it 8 times. You can now access some of the weapons that are usually blocked. Plus the Ninja rope is extra bouncy.

Hint:
On Worms select the Ninja rope, (second weapons menu) and aim it at the ground.Fire it and press down and a direction button. Well done! You can pole vault! This is very useful when getting over obstacles.

Infinite Banana Bombs and Mini-gun:
Go to options and select weapons and press Square button 6 times.

Boxing Ring:
While playing, execute a fire punch or a dragonball, then quickly hold SQUARE and press R1, L1, Circle. If you did it correctly, one worm from each team will be teleported to a boxing ring where all you can do is punches and dragonballs. When one of the worms dies you will teleport back to the original landform.