Only, very few notes:

You can't compare FarCry with Crysis, the first was a success, the second wasn't, for good reasons. IMO, the demo of Crysis is a mess, there is no fun at all, while I enjoyed playing the demo of FarCry for hours, and it is one of the very few games that I bought in the year after it was published. And, I never was tempted to stock piling any weapons. I think that FarCry actually is a game that you can play the way that you described about playing Unreal. You don't need to care about the story.

Another game is Gothic, I never played its whole story, I'm absolutely bad in role playing, because I don't care of careers and rewards.
BTW, I didn't play through the whole story of FarCry, too.
Nonetheless, I played FarCry and Gothic for hours, enjoying to discover the landscapes, to fight against (often, too) strong enemies (because I didn't level up), trying to trick their intelligence, trying to isolate single enemies from their group, and got defeated by surprise attacks, because I didn't expect them to follow me at such hidden or 'safe' places where I escaped to.

Don't miss to play FarCry, it _is_ K.I.S.S., and it has its very own challenges.