I'd have to say that's a very decent effort for a first short. I liked the editing with the gun and saying "day after day after day". Was the coffee cup a godard homage? nice touch. Obviously at this point every element can be improved upon. For starters, I think most of the dialogue was decent, but the flow of the characters was a bit jumpy if you know what I mean. You have to get in their head and respond to the situation as opposed to just making them do or way what you want to be said or done.
The sound is something that could easily be improved upon to give more dignity and viewing pleasure to your piece. The acting needs work also but that will take more time and practice.
Well everything takes time and practice but keep it up, your off to a good start.
The editing would be something to focus on for post.
Obviously you used a cheaper camera, but I think you did a good job with it. Be careful about what shots you cut between, keep the 30 degree rule in mind. Don't go from one shot to another where the difference in angle is smaller than 30 degrees, most of the time its an awkward cut although I've seen it work. Focus on how your using your camera before you jump to a better image quality. I think a lot of people jump up to a camera they are not ready for because they think the pretty colors will make up for amateur cinematography. maybe for techie geeks thats fun but not for artists.
keep up the work, you'll be surprised how much you improve from one project to the next.