The worst yugioh game on the ds, in my opinion.

In order to unlock packs, you need to clear certain "theme" or "limited" duels. You can cheese the limited duels by using 40 trap cards, including trap monsters like Zoma the Spirit.

The theme duels are really lame because you won't actually have the resources to build a cool deck that fits the theme. Instead, you're just stalling until you can meet the requirements. Might be more enjoyable if you cheated to get every card early.

Duel puzzles are fun tho.