Well the game is simply awesome .... both gameplay wise and graphics wise .... in fact .... even if u haven't played the first game ... u'll still be stuck with this one for hours ... ....
The weapons are awesome .. specially the "Gravity Gun" .... and every weapon has its own usage ... which u must find out .....
Environments vary from wastelands to infected towns to beaches .... the scenery is too good to miss .. specially if u have a good rig to handle it .....
The story is awesome .. and the ending is worth playing the whole game ....
check out this link for some ingame screenshots : Link 1 Link 2
sorry for such a short review ... trust me u wont be dissappointed with the game .... oh btw .. i played the game on the following config : P2 2.66 GHs , AsRock 865 Mobo , 384 MB ram ... it ran smooth at the auto-detected settings ....