Took the words out of my mouth...The Lunatic said:Because it's your typical "Story second, shooting and explosions first" kinda shooter.
Little depth to the world, little storyline involvement, just, go here, shoot these guys.
And in doing that, it did fine. However, the PC market tends to require games that have more depth than that, so I don't recall it selling very well. Of course, Crytek blamed Piracy rather than themselves.
This is why the more "Hardcore" fans like games like S.T.A.L.K.E.R and Metro, the world has depth and meaning.
It took a while to figure out, but I eventually discovered that I find myself far more engrossed in games (not just shooters) with established worlds themes and continuity to them.
That's probably why I love Shadowrun (tabletop) so much; it has a very well-written and firmly established timeline with changing political social structures and events; yet you can play virtually any era under the same rules (prior to 4th edition anyway).
The only real exceptions that come to mind are games of strict competition. UT2004, doesn't really have anything going for it in story (UT3 embarrasses itself trying to explain its competitive game mechanics in the real world. Even Tribes Vengeance did a better job of that).
When I first played Crysis, I was genuinely impressed with the visuals and a few of the game mechanics, but everything else felt like a mechanical retread of Farcry. Fine, if you were looking for a more open-world FPS, but it wasn't much for exploring unlike the smaller-scale "First Person-RPGs" (Deus Ex, STALKER, etc).