Depressing and the end was....(spoilers hidden)
....cliche to some degree. Firstly, it was the most depressing zombie flick I've probably ever seen. The end with her shown well into a pregnancy felt kind of "tacked on" to me and it's overused in too many films. As far as her tracking them(her brother in-law and wife) down for revenge seemed improbable, especially with her pregnancy, do they deserve to die? To her yes, but there is a point where you need to move on even when people screw you in terrible ways if you are planning to make a viable future for yourself and your child. I'm sure it's something the makers thought would seem clever, but not so much.
I liked it, don't get me wrong, it was a decent switch from the usual zombie crap, I just didn't expect drama/humanity to be the main course with a side of horror, instead it was reversed and that's ok, just know what to expect and you'll be fine.