Defeat 30 enemies with the Moss - 12

Destroy 100 enemy vehicles.

Defeat 30 enemies with the RPG - 7

Defeat 50 enemies with stealth attacks

Defeat 50 enemies with the Dragon Sniper

Defeat 30 enemies with Mk-NDI grenades

Defeat 20 enemies with a single punch, after softening them up with gunfire

Collect 60 coins

Defeat 20 enemies with headshots

Defeat ten enemies in a row with hand-to-hand combat

Unlock the Grail Knight.

Complete all Story Mode Levels in Skull 2 Hub.