ooh, this is pretty good =) the not very many bullets/slow shooting definitely gives it a different dynamic than other games of its kind.
the sound lags to a ridiculous degree for me, though, either playing late or not at all. also, you should add some specific key to be pressed in order to restart; as it is right now, i am always trying to run away when i die, and so am pressing one or several of wasd, causing it to restart instantly before i can see the final score.

http://davidgomes.github.com/paxlure/

The game can now be played there btw

@shmbis: the sound doesn't lag for me in Chromium, it works every yes every no on Firefox, and never works in Midori :S

Here you can see the sound code, if you're interested.

@DJ: That was a hard decision. But what if the player runs out of bullets, and when this happens there are lots of zombies, it would be worse for the player to find the ammo.

However, there's an even better idea, which is to have a "Catch this, it's ammo for your shotgun!" on the first bullet. I'll try to do that