When you take into consideration the budgetary constraints, including the inability to afford professional casting, you can pretty much tell when you are getting an amateur writer or filmmaker who has a noticeable amount of promise or possibilty, and when you know for certain that they are headed nowhere. That is when it is abundantly clear those at the helm of the more awful low budget creations have no skill in presenting believable or passable scenarios, and are unable to recreate any observations in human behavior, how people act and talk in any given situation, whether dramatic, comedic or genre heightened.
This is one of the latter. There is a concept known as "verimilisitude", which is the idea that it doesn't matter if your concept is set in hyper reality, in outer space, or in a child's animation, if you don't buy into a personality or situation in order to suspend your disbelief, the entire effort is an abject failure. From filmmakers, to stand up comics and other storytellers, this is an essential facet of a creative arsenal.
There is just no reason any filmmaker should have such bad plotting, characterization and dialogue as this. I can forgive bad or amateurish acting, but maybe the issue is they have nothing to work from.