Good, but could be better.
All-in-all, I liked it, and I think you've lived to the standard you've made with your other games.
It was a fun game; it was made and animated well. The sniper rifle was a ton of fun, and the berserker and the last zombie were great boss concepts. The wrist computer was a good idea, and it helped a lot during the area with the snipers. However there were a few things that bothered me.
The day and night system was not a good part of the game, since all it really did was make the area darker so you had to wear the night vision goggles. Although I thought the goggles were interesting, they didn't hinder you or anything; it was just an annoyance that didn't add anything significant to the game.
Also, since you have unlimited ammunition, what was the point of the pistols? Yes, you could use the shield with one, but honestly, that was only useful against the zombie with the chaingun, and even so, I did not feel the defense was worth sacrificing the firepower of the M16 or shotgun. That might just be because of the way I played, though.