The game's gameplay shares similarities to other role-playing games, notably including the Pokémon ones, as the player has to choose between the four characters, to attack a monster each time.
Each character has three abilities: a common character move, an ability that either heals or protects him and others, and a special one. The latter two can be unlocked, speed up, and upgraded, through winning a battle, which gives you a level point (LP). They can be also spent for up to 3 costumes of the playable characters, with each one also having their individual abilities.
Patrick: Stand Very Still, Hide Under Rock (prevents all damage from the next enemy attack),
Sandy: Howdy, Science (adds a random weakness to the monster)
Squidward: Nag, Dance (character abilities become ready faster)
There are three attack types in this game: Sound (ear), Sight (eye), and Smell (nose). They can be seen alongside the outfits in the outfit selection screen, and alongside monsters the player has to deal with during gameplay, representing their weakness.
SpongeBob SquarePants: I'm ready!! I can't wait to explore Monster Island again!
Squidward Tentacles: We're only here to serve Krabby Patties, SpongeBob.
Patrick Star: Too bad we don't know who they are going to, though..
Sandy Cheeks: Look sharp! The monsters here will take our Krabby Patties!
SpongeBob: We've gotta get past these monsters - for the customer!!
Sandy: According to the map.. we need to go through six zones.. to reach our Mysterious Customer!