This requires a Wii with internet access. Enter the "Avatar" menu and begin Tag mode. On the Wii, go to the Nintendo Channel. Enter the DS Download Service. Select a demo and have the Wii prepare it for download. When the Wii is transmitting the demo, an avatar balloon popup will appear after a few minutes. Select the balloon and use the scratch card. Exit the transmitting demo screen and go back into it. Select another demo on the Wii and repeat the process.
To unlock the secret ending in the theater mode, you have to collect 20 trophies or more.
Complete the game once on any difficulty and Theater mode is unlocked. You can watch any Cut Scene in the game as many times.
Get avatars in tag mode only using one DS system
For this to work, all you have to do is go into tag mode and let your system run. Even if there aren't any other transmitting devices (like other DS or a Wii) around, you will eventually meet randomly generated artificial avatars. It's pretty random, so sometimes there will only be one encounter in one to two hours and other times there will be several encounters in half an hour. Those avatars work just like any real avatars and they will provide you with scratch cards, let you build your avatar sector down to 100 floors and you can get all available avatar parts from them.
To get a Trophy, you must meet certain conditions in the game. There are 30 in all. Each one provides a chip for the Stat Matrix that boosts HP by 2, Strength by 1, Magic by 1, and Defense by 1. Also, collecting 20 allows you to look at the secret movie video.
How to unlock
Get 50+% of the Avatar Parts from the Avatar Sector.
Complete all 100 floors in the Avatar Sector.
Find 70+% of all items, cheats, chips, weapons, and abilities.
Use every one of the cheats.
Finish the storyline.
Converter LV. 100
Bring one command to Lv. 100.
Converter [CR] LV. 100
Bring one command to Lv. 100 with the [CR] labeling.
Complete all worlds on Critical difficulty.
Defeat the Eliminator.
Complete a world, start to finish, with the HP Cheat set to 0%.
Beat the Ice Titan in Layer 30 of Olympus Coliseum.
Justice for All
Defeat all kinds of enemies, even bosses (except the Buggy Roxas of Hollow Bastion's System Sector), at least once.
Lord of Loot
Learn 80+% of what enemies' drops are.
Complete all worlds on Proud or Critical difficulty.
Finish all quests.
Rare Prize Roundup
Find all Rare Prize Blox.
Find and finish all floors of all System Sectors, even the extra ones.
Sultan of Slot
Put one chip of any type in every slot of the Stat Matrix.
Complete all worlds with a Level under 15.
Defeat the mystery opponent of Castle Oblivion.
W1 Speed Runner
Complete W1 (Destiny Islands) in 5 minutes or less.
W2 Speed Runner
Complete W2 (Traverse Town) in 15 minutes or less.
W3 Speed Runner
Complete W3 (Wonderland) in 15 minutes or less.
W4 Speed Runner
Complete W4 (Olympus Coliseum) in 10 minutes or less.
W5 Speed Runner
Complete W5 (Agrabah) in 15 minutes or less.
W6 Speed Runner
Complete W6 (Hollow Bastion Part 1) in 15 minutes or less.
W7 Speed Runner
Complete W7 (Hollow Bastion Part 2) in 30 minutes or less.
W8 Speed Runner
Complete W8 (Castle Oblivion) in 10 minutes or less.