I think with the type of short film that this is (sort a narrative reflection on the guy's life), you really shouldn't have his face introduced in the first shot - normal set ups for films start off with an establishing shot of the scene, in your case a couple of shots of the city or something like that would suffice.
With the film being set up to be a very internal story, it's an odd choice to have developed the woman's character at all, even if you did so very briefly. Your film would have benefited a lot from being a completely internal story without external characters. I know that's a hard thing to do with this, seeing as the whole thing is that he kills people, but if you'd gone along with a story that focused a lot more on his coping with the knowledge that he'd killed people as opposed to bringing in the female as a main character (which I feel you've done accidentally, but having him let her go when he saw her family photograph basically makes her an important part of the story) I think it would have been a lot better. Imagine a scene basically the same as the one where he let the woman go, but instead he kills her and then finds the photograph, reflecting back on it later when he's in his apartment and going through essentially the same thought process.
That end scene where he gets killed... I dunno, it just didn't feel right. The whole film seemed too fast, and I think your main problem is that you've tried to fit too much of a story into too little a space, making it feel fairly rushed. The sound quality was fine, as was the image quality, but I think more planning should go into the shots.
tl;dr: lengthen the film or simplify the story further, and plan it all out a bit better.
