First of all, this movie is currently tagged as "horror", but it's primarily a comedy. In fact, I wouldn't call it a horror at all. I'd call it a dark comedy, if anything. Just because it has a corpse coming back to life doesn't mean it's a horror movie.
Secondly, I've seen a lot of low-budget movies, ranging from terrible to brilliant. The bad ones suffer from bad acting, uninteresting or nonexistent plot, terrible dialogue, bad camera work, and boring, unrelatable, unlikable, and stupid characters that make you wish they all die a horrible death really soon (see 'Safety in Numbers' [2006]).
Ground Zero is nothing like that. The plot is quite simple. As the description says, "A small group of 'cleaners' are hired to clean up five dead bodies in an old warehouse, only to find out that one of the bodies isn't quite dead." That's about all you need to know without spoilers. The plot is coherent enough and doesn't suffer any problems.
All four main characters are acted out pretty well. It may not be award-winning performances, but at no point did I feel like the acting was bad. That is, by the main characters. The weakest point of the movie is the first 6 minutes, before the main characters appear. This part may create a false impression that the movie is going to be bad. Once Jairus and Greer appear, the movie picks up quickly.
The characters are well-defined, relatable, and likable. Not like in those movies where you can't help but think that all these stupid and boring people should just drop dead. Here you get a fairly clear idea about what each of them is like, and they feel real enough.
What makes this movie good is the dialogue. Again, starting after the first 6 minutes. For a low-budget movie, this is really well written. The dialogue goes far beyond what the storyline requires. In many other movies, the dialogue presents only the bare necessity to make the plot work at all, but everything is dull and uninteresting. Here, the plot is the backbone that holds the movie together. The dialogue is the flesh. It's what makes it interesting and sets it apart from other movies with reanimated corpses. The dialogue not only creates the characters' background and moves the plot along, but also makes each scene interesting on its own. You can watch 10 minutes somewhere in the middle of the movie and enjoy it without knowing the plot, because the dialogue is interesting and often funny.
The plot in the second half gets actually more interesting than I expected, though I admit I didn't expect much. Still, the way it all plays out at the end is pretty cool, makes sense, and wraps up the story well.
As long as you know what you can and can not expect from very-low-budget, the-dead-coming-back-to-life kind of movies, you shouldn't be disappointed with this one.
