I enjoy the Sniper Elite series, but this game doesn't really compare. It's the arcade version of what a hastily-thrown-together version of a Sniper game might look like. There's really no story to speak of and a decent amount of the content isn't even accessible without a co-op partner or three. The game was clearly designed with that squad-based co-op experience in mind. I didn't really know what I was getting into when I bought it, because had I known that I probably would have avoided it in the first place.
The worst part is that the gameplay seems to have forgotten the name of the series: the emphasis is not on sniping at all. And there aren't any fun stealth moments either. There are far too many zombies at far too close a range. Instead you're much better off using explosives and automatic weapons if you can find them and just going in loud every time, in every situation.
If that's the kind of game you want then I can understand that, but it's not what I wanted from a Sniper game.