Lost Kingdoms

Hints
Duplicate Cards:
Using 2 controllers and 2 memory cards copy your data to both cards. Then load both profiles in two player versus mode and have the "losing" player bet the cards you want, and the "winning" player bet some weak cards. Make sure the "losing" player loses, and save the prize to the "winning" card.

One-Hit Kill on Last Boss:
Use the Doppleganger card and it may kill the boss with one hit. Note that you will need to upgrade the following cards to 9,999 EXP Points:

#45-Great Turtle
#69-Blue Dragon
#83-White Tiger (Rare card, make a copy first)
#104-God Of Destruction (Rare card, make a copy first)