Unlock the following bonuses by completing the game on the corresponding difficulty levels:
BONUS - DIFFICULTY LEVEL Art Gallery 1 and the Cabal guns - Easy difficulty .50 Desert Eagle - Normal difficulty Molotov cocktail and the expert difficulty setting - Hard difficulty Rocket launcher and Cabal rifle - Expert difficulty Cabal SMG and the Art Gallery 2 - Successfully complete instant action mode under the easy difficulty setting. Extra Adrenaline - Successfully complete instant action mode under the normal difficulty setting. Extra Health and the expert difficulty setting - Successfully complete instant action mode under the hard difficulty setting. Extra Ammunition - Successfully complete instant action mode under the expert difficulty setting.