Renji
Collect 50 cards to unlock Renji.

Renji's story
Collect 70 cards to unlock Renji's story.

Mini-game
Collect 100 cards to unlock a mini-game.

Blockon multi-player mode
Collect all 134 cards to unlock Blockon multi-player mode.

New items
Every time you buy ten cards you will unlock some thing different.

Courtesy of CheatCC