Duel Masters: Sempai Legends [GBA]
After you beat the game and defeating Mr. X, you will unlock the "Duel Room" at the main menu.
In a trade shop, save and quit. Select "Continue" and in "Special" you should have different cards.
When you first start the game and it is at your birthday, someone comes in and steals your rare family heirloom card. You are then sent to find the detective. Turn off the game and do not save. Start the game from the "Continue" option and choose a different type of deck. Go to the trade center and go to "Special". Your former "heirloom" card will be up for battles. Do this with each of the different types of decks.
When you choose your deck, choose the Fire Deck. Later in the game you will get Bollshack Dragon.
The best deck to use is the Light Civilization deck.
Save in the submarine:
You can only enter the submarine after you have accepted the last plaque. Stand outside the submarine, press Start, highlight "Save" and walk into the submarine. Press Start and notice that "Save" is black, and the pointer is on it. Select "Save" to save your game. As long as you do not move the pointer away from "Save", you can repeat this as many times as desired.
Trade shops are useful throughout the game. The best is the special section. It has a lot of rare cards (for example, Metalwing, Skyterror, Bolshack, Dragon, etc.).
Save when not available:
Walk or run to any tournament. Stand in front of it and save the game. Then, enter the tournament door. Press Start and the arrow will be on save, but it states that you cannot save. However, press A and it will save.