FlashtooREV stole the words from my mouth...
Well, for your first game, it's really good, and I'm definitely impressed, so you should continue working on it ;).
The gameplay was OK. I liked the choice between easy and hard (no medium though :P), and the briefing idea was good, since it's boring just seeing your mission objective pop up on a screen without any storyline to it.
It progressed pretty well too, but I think that easy should fit in medium, and you should add an easier mode. Easy's supposed to be just to get used to the game, normal to play it with some difficulty in it, and hard if you want a challenge. I'd suggest making the lives or time vary according to the difficulty. Good idea for the three locks, by the way, and I liked the fact that there was a gallery.
The zombies' groaning sound effect was OK, but there needs to be more sound effects to it, like the zombies shouting out when you shot them, the sniper shot, etc. The menu music fit very well, but there should be some more music in some parts, like some slow 8-bit music in the background, and a small 8-bit 'game over' melody when you lose a life.
The graphics weren't that special, as FlashtooREV said. Pixel art was OK, but the background didn't change much, and didn't look too good either. The sniper's vision was quite messed up too.
All in all, for your first game, it's great, and I'm sure you'll continue to be an excellent flash animator at this rate. Keep it up!
7/10
4/5
-Review Request Club-