Its not killing other people thats the problem. Its the game.
SP or MP, of the controls are clunky and the guns svck its not going to be a fun experience.
Ignoring the MP issues of lag, hit detection and camping. It still dosent make a good game, definately not something worth the money.
Shame because it had potential Crysis 2 = Section 8 all over again.
The guns weren't very "good" in the first Crysis either. I recall shooting someone 15 times in the first one before they would die, in extreme cases. I'm going to go out on a limb here and say that EA pushed them to hard, though I have no real facts for that. I wouldn't be surprised if it was "strongly encouraged" for them to focus on the multiplayer aspect of the game more. I don't really remember anything about the controls on the first game, I'm assuming if they were bad I just remapped them.
If you ignore MP issues that pretty much leaves you with the gun thing and the controls, controls can be rebound (on consoles too I assume?) and they might have been trying to keep with the tradition of the original. Also bad registry could be making it so it seems like it takes a lot more bullets to kill someone than it actually does. I'll wait and read reviews, but very few FPS games are worth $50-$60 for the SP; mainly because they try to push out a half-assed multiplayer in my opinion.