4. Cliffhanger - Modern Warfare 2
A lot of the love for this level stems from that Hero Moment when Soap saves your life as you head towards the icey peril of a sheer cliff face, but it's not something I could love immediately having died immediately on my first attempt. Anyway, those issues resolved, Cliffhanger was able to extend its cool grip around me as well, with its excellent design and fiendishly clever infiltration objectives. Yes, you might have got the objective for not killing anyone at all, and probably tell your friends as much all the time, but I like explosions and immediate threats that kill me multiple times before I can best the level. If I wanted to creep around not killing anyone I'd play out in the real world, thanks very much.