Crysis 2 succeeds in crafting it's own identity and style, while encompassing the sense that the developers actually gave a shit about what they were doing. The campaign is long, the level design is good, it's different to the original Crysis but there are also some improvements in some areas, the combat is satisfying, and the pacing is quite impressive. It doesn't feel like 'another FPS', even if a couple of levels dip in quality.
It's the kind of game you cant go "Oh it's like XXX". Crysis 2 is Crysis 2, unlike most other games on the market, and for that reason is worth looking into in my opinion.
I dont think it holds a candle to Half-Life 2, and it's not without flaws. The tutorial drags for far too long. There's a few dud levels that reel the game back into generic territory, though they dont last long. The story is shit. The AI can be hillariously stupid, and there are a few bugs.
But the art and graphics are gorgeous, the city is a joy to behold and traverse, and the combat rarely, if ever, becomes tedious or boring. It's just fun.