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.

Sure the game might not be optimised properly but don't say that the controls are broken/flawed just because your computer can't run this game smoothly