Not easy...
5 - God of War: Chains of Olympus
4 - FF7: Crisis Core
3 - Warhawk
2 - Uncharted
1 - Super Mario Strikers Charged (which I'll finally purchase my Wii for)
I don't want to get way off topic, but does anyone know of a harder Mario game than Strikers for gamecube? The 2nd hardest difficulty almost requires that you have at least 1 person to help you with, and is very hard unless you have 4 people all playing together that know what they are doing. The hardest difficulty is extremely challenging but a lot of fun to try to conquer. The unfortunate part is that I never got enough time with my friends to do it. I was hoping the online options would include 4-person games, but apparently that is not to be unless you have a friend and you play online with 2 people together as well. Even then I'm not sure you can play against the computer...I hope you can.
Anyway, if there is a harder Mario game I'd really like to know.
Edit: Man, I forgot about TF2. That looks amazing. If they supported keyboard/mouse for PS3 I'd put it on my list (or if my current PC could play it).
