Not bad...
LOL love that ash is using a musket! LOL
Here are some tips. Rework your sound, better synching on your dialog and such. The sound needs more layers but not actually in the foreground...don’t know how to explain unless you are using an adobe premiere or something like it. The zombi grunting needs to replace (sounds like it came from a zombi Lego short) with actual sounds that come from the actor. Use your locations more. That long abandoned walkway in the beginning was a great shot. Don’t use plastic gun unless it’s a quick cut. Unless you can afford those decent reproductions and find dummy bullets at the army navy store don’t use plastic if you are going to linger at the scene. Shorten cut down on the scene where there is nothing going on. A few times i counted to 7 or 10 and nothing happens. I’d say no more than 3-4 seconds. Have all your actors rehearse at least twice for each scene. The gore effect are ok but look at some you tube vids on how to make alot of cheep blood (kero syrup and food coloring) and guts...you might have to go to the local butcher for intestines and such. Do not rely on cgi gore. Use it with real gore. Use you tube and you ingination on how to apply it.
You have some excellent shots like the begining. Some good action scenes and a good overall short film. Looks like you had an excellent crew and actors. Thats hard to pull off itself.
Dont take this responce to hard. Everyone is a critic so be patient and keep at it.