I say turn on everything but black eye(and iron if your solo) Thunderstorm and mythic just make it harder to kill people, so it's funner. I don't even notice Fog, usually the enemies are always in front of you. Tough Luck is easy too, you can still get good grenade kills when there are 3+ enemies, especially when you catch them off guard. Famine is challenging, but when you get weapons from drop pods and the purple crate things, they usually have enough ammo. and you can always take your ally's stuff. Tilt is tough, you have to be prepared with the right weapons. If you do all these (and iron) on normal co-op you can get like 100k points with the time bonus multiplier. On heroic(2x) + skulls (15x) and a time bonus of 2x, you'd get 34x multiplier. [Edited on 10.03.2007 8:35 PM PDT]