It could be a cheap birthday present for your little brother, but the violence makes you choose something else.
First of all, the story is quite good. The idea is good, but when it comes to realising the idea, it all collapses. The whole story consists of a recollection of some guys recent happenings and the flashbacks have some flashbacks of their own. The interface and gameplay might confuse you at some point. You must not confuse it for a RPG style shooter like GTA because the gameplay is really linear.
The gameplay and controls are bad but not too bad. They are a bit raw compared to other games to the genre like GTA and lack smoothness. At some points the controls might stiff up. The gameplay looks big because you see big rooms with big crates and many rooms, but the path is clear and the level design does not really give you any choices to make. There are some arcade style opponents, like a sniper in a helicopter (you will probably encounter him before the game gets too boring) whom you have to shoot thousands of times and even then he just says that he is 'shot' and flies away. The graphics are terrible. Comparing them with state-of-the-art games would be completely absurd, but comparing it with the original Half-Life would be fair. The ingame movies do not look good either because of the low resolution and the sometimes stiff animation. Although the graphics are poor, there are some long loading times that would not bug anyone if the graphics were better and the levels a bit bigger. The sound is a bit messy at some points. It is extremely messy when someone is speaking about vital stuff like how to get past some guys or where to proceed. The vocals are too quiet for default and if you even prick your ears and try to configure the settings... you will just find that some vocals are still too unclear. The vocal acting is not anything nice either.
The best thing about this game is the story, if you have the nerve and simplicity not to mind the minor inconveniences and the lack of ... lack of all the things that the game lacks of.