"Metro 2033" was more of a labor of love of turning a novel into 'visuals' than a video game. The amount of thought put around every corner guaranteed a one-of-a-kind-creepy experience. I played it on the PC, but back then my machine couldn't quite handle it... so I rented the game for the 360 (so yeah, the PC version wasn't legit).

It had some of the creepiest stuff in a game, and the realistic atmosphere added to the experience. The sequel is going to be way better than the first, the fact that the game devs listened to player's complaints (like having to check the watch to see how much oxygen is left, tedious aspects of the game has been simplified).

Oh and also the game is going to use some of the most advanced visuals... but they have guaranteed it will be playable on current systems and not a military grade machine at max settings.

Bad control = lag? As the visuals are turned up higher, it seem like it is going to be fine but once you start moving around, the lag is pretty nasty and you feel it the most with the controls. There will be noticeable "delays" between one movement action to the next (as is the case with all games).
For "Metro 2033", the lag means the difference between being alive and dying.