I have to say that I watched this film with reserved expectations, for me independent films carry with them a certain stigmata. Unlike a blockbuster that can cover poor elements with budget or cast, independent films feel a lot more exposed to criticism.
The good news is, because I had managed my own expectations what I got was a very enjoyable story-led, zombie thriller. I was engaged with the characters and story because throughout the film I felt genuine tension. The score and cinematography were superb. I often caught myself admiring the quality of the shots, the consideration of the angle and the accompanying score. There was one particular shot of the Isle of Skye that was stunning.
One previous film likened this to a 'Poor man's 28 days later', well I actually consider this to be praise. I love the atmosphere and style of that film and for Plan Z to compared I think is a great feat considering the difference in cast and budget.
If I had to be overly critical, there was one plot point that left me confused to what actually had happened (I don't want to give away spoilers but it's a major point of the film) and there was one piece of music towards the end of the filmed that didn't like it mixed very well and was out of place.
When watching, please don't expect a Hollywood blockbuster or compare it to the big Zombie films as it won't compare. Have a bit of perspective to how it was achieved and I think you will be very pleasantly surprised.