Quite good, but...
There's one thing that really got on my nerves - most of the weapons are useless. In the later missions all I wanted was a normal machine gun, instead I got some kinda "spread-gun", some kinda laser and seeker missiles. You're probably thinking "that guy had a rocket launcher in a shooting game and he's complaining? Idiot", but rockets practically useless against hordes of enemies, as it kills only one guy at a time and you have about a hundred coming at you. The winds also got on my nerves, but I put it on difficulty of the game.
The graphics are quite good, so is the sound. There are a lot of different enemies carrying quite a wide range of weaponry.
All in all, it's not bad and I'd like to play it 'till the end, but the weapons really fucked it all up for me. Still, i's a nice work...