I'm going to get the 'elephant in the room' out of the way at the beginning. On a technical level, Crysis 2 on the PS3 is supposedly the graphically weaker of the three versions of this game. Importantly though, that shouldn't prevent anyone from buying it.
Once this is plugged into an HDTV you really shouldn't care less what it looks like on other systems because here it is absolutely stunning. Everything looks really good from the devastated architecture of New York to the weather effects, allies and enemies you come acrosss. Water, fire, smoke and dust are immersive and convincing, and the lighting has to be some of the most advanced out there right now. The greatest credit to the visuals on show here is that by the end of the first level you will stop being gobsmacked by how good it all looks and simply accept what is put in front of you. It's hard to describe, but the art design here is geared towards making the in-game objects/environments feel real, huge or frightening, rather than simply aiming to make them 'look good' on a technical level.
The frame rate isn't especially slick (but is still perfectly playable) and you occasionally catch a tiny amount of motion blur in the characters, but these are minor points compared to the overall experience.
The rich audio is impressive; from weapon sounds to creaking buildings, and the sound designers know how to creep you out when they want. The soundtrack is a mixed bag, with the first main theme having a real 'dirge' sound to it, but there are also some great orchestral numbers in the vein of classic action movie scores as the game progresses that you'll have stuck in your head afterwards.
The gameplay is flexible, as each level is basically a giant sandbox. You have a visor that you can activate to highlight different tactical options, but there's nothing to stop you inventing your own unique way of dealing with a situation. The advertised stealth ability doesn't make you invincible as you can be detected up close as enemies see a 'shape' coming towards them, the same as you will when a cloaked enemy approaches, so you still have to pick your moment to strike or sneak past. Your suit has a number of active and passive abilities that you can customise as you go through the game, and you can customise your weaponry in the field once you find a safe bit of cover. Most levels have a large amount of vertical freedom so you can find a high point to observe the enemy and plan your assault: just be careful not to be spotted by snipers as you make your way up...
Your suit has a certain amount of energy that drops quickly when you use special abilities. It does recharge once you stop, but this does add a neat tactical element to combat as you will have to think through difficult situations before you enter them if you want to survive.
The sci-fi story is clever and ambitious (dealing with themes of transhumanism and corporations rushing to be the first to implement technologies they cannot fully control), but as usual (for a shooter) it suffers A LOT from the way it is told through on-the-fly encounters and radio transmissions. There are very few games involving any kind of shooting that get storytelling 'right', with Bioshock and Mass Effect 2 both being notable exceptions.
This is one that you should definitely try if you fancy a different twist on the genre and aren't dissuaded by those claiming that PS3 owners have in some way been cheated by this release. We haven't; this is an amazing game that any action fan should play.