Mario Double Dimensions is a game that features both 2-D side scrolling play and 3-D play, similar to Super Paper Mario.
Mario is walking along the beach when the earth shakes. He turns to see the castle under attack. He runs over there and when he gets into Peach's room he is just in time to see her be teleported away. Toadsworth then comes out from behind a chair and tells him he knows a man who can help you get Princess Peach back. He goes to the house where this person should be and finds a completely empty house. Then suddenly he feels a strange force tugging on him and is then teleported to a strange world where everything is paper-thin and negatively colored. An old Mushroom Retainer approaches him and tells this place is a parallel world your own know as the The Land Of Negativelry. He then says the maiden you search for is trapped somewhere inside this realm. Finally he gives you a Jade Crystal and says " Whenever this jade meets another world, you will be switched and your dimensions flipped." Then you start to travel all over the place using the jade to help you complete puzzles and travel further. After awhile you learn that Bowser is not the enemy, a strange being known as " The Neutrass " is the real bad guy. After that he starts sending in enemies of his own such as Photors and Gluonaters. Then you meet up with a strange woman named Savidas tells you of Neutrass's plan to use the princess's pure heart to completely "negate" your own world. She then agrees to join you and help you and your way to finally finish "The Neutrass."
Both dimensions feature different play. The "normal" 3-D world works alot like mario galaxy, even retaining gravity effects in some places. Similarly, the "negative" 2-D world is essentially the same as Super Paper Mario but you are able to use attacks.
Trophies And UnlockablesEdit
Throughout the game you can attain trophies. These trophies have little effect on gameplay but have stunning graphics and count towards your completion %. Trophies can be purchased, found or be created from enemies. Each trophy has two versions; the 3-D normal world one and the 2-D negative world one.
These characters can be unlocked by doing certain things. They are not needed to complete the game but they count towards your completion percent and are needed to find certain trophies.
Luigi can jump higher to get to high up platforms that Mario wouldn't be able to reach and he can also run faster to to do stuff Mario isn't fast enough for.
Wario is both slower and can't jump as high as Mario but he is stronger and as such is able to lift and push objects Mario would be otherwise unable to do. When he has obtained a fire flower he'll pass major gas that rockets him into the air ( higher than Luigi could ever hope to go ) making it both a useful attack technique and good for reaching really high places.
Waluigi is somewhat faster and can jump somewhat higher but is not nearly useful that way as Luigi is. However he can throw bombs that can break through objects that punches can't. When he gets a Fire Flower, he doesn't throw fireballs instead his bombs get a bigger blast radius.