Special costumes
Press F12 at anytime and a window will pop-up. Enter the name "PLANKTON" to activate the code that will unlock 4 special costumes, which Spongbob & Patrick can wear. Find the ICON that looks like a stack of clothes. These will only appear after you enter the code, so you may need to explore areas that you have already visited.

Extra long enemy antenna:
Collect 3 treasure chests.

Mermaid-Man costume for Sponge Bob:
Collect 2 treasure chests.

Film Trailer 1:
Collect 1 treasure chest.

Film Trailer 2:
Collect 6 treasure chests.

Bad Guy sound pack:
Collect 5 treasure chests.

Sponge Bob art pack:
Collect 4 treasure chests.

Get Dennis:
Dennis will use Sponge Bob as a hockey stick and hit toilets at you (which means you are Patrick). If you upgraded Pat's Star Spin, use it to hit them back at him. The entire battle remains the same, except after a chunk of his health is gone enemies will appear and spin attack you. Jump on their heads. In part two of the battle, you will be Sponge Bob. Dennis wil throw daggers at you. Just dodge them. Attack him with a Bubble Bowl. Again, the fight is the same, only fish with giant crowbars will try to hit you. If you upgraded your Bubble Bowl, detonate it between Dennis and an enemy if they are close.

Get the frogfish:
The fight starts with Patrick. The frogfish will try to ram you at first. Dodge it by cartwheeling out of the way (because Patrick is so slow). If it hits you, hit the old lady on its tongue. Once you clear the green part of its health bar, it will jump to another platform. It will dig with its tongue and try to hit you. Hit the tongue. Keep repeating this. When the fish jumps to the other platform, the tongue will do a spinning attack. Slam it !

Get Plankton's statues:
To defeat the giant statues, hit it on the eye with a Sonic Wave Guitar Attack when it is open. However, they can also attack. The first is easy. It will shoot big molten rocks at you. Wait until half a second after the eye closes and start the Sonic Guitar. It should be open by the time you hit it. The next one is easier. Stand on the platform to the left and its eye will try to shoot you. Jump to the right and use a guitar. The next two are the easiest. There will be enemies guarding them, but they are pushovers. Hit the missiles that they throw at you back at them (via the Macho Karate Spin). Then, one eye will open, attempting to send out more enemies. Just hit the eye. Do the same with the other one. The last one is actually a mini-Boss (although it has no health bar). It takes three hits to defeat it. First, take out the three enemies in the middle platform. then go to the closest platform and kill the enemies as you go. Next, jump on the springboard and prepare for a fight. The conveyors will start moving and the eye will open. It will shoot a laser at the front conveyor belt, and also shoot out a ball of lava. Wait until it is done, then jump to the front belt. immediately use a Sonic Guitar. Do the same thing two more times to win