[quote][b]Posted by:[/b] imperius iv I like to use Tough Luck, Thunderstorm, and Famine on Heroic. Makes it just about perfect for me. Hunt down dodging, high ranging killing machines, scrounging for ammo... [u]plus Cowbell and IWHBYD make it perfectly balanced for my skill.[/u] Haven't tried online co-op, though. Every skull must make the game near impossible. I had a hard enough time on "Cortana" with just legendary, no skulls.[/quote] Hate to break it to you but IWHBYD skull does nothing except on the last level aat the last terminal, but if it helps you in any way what so ever, kudos on something i did not know was possible.