Not bad, although there's room for improvement. I liked the concept, and it seems like your camera skills are improving. I like the tone you created as well. Not through color grading, but there's an underlying sense of dread that I think you really captured with this one. Much like your second short film. Anyway...
I don't like the title in the beginning. It doesn't fit the tone of the film. Perhaps something more textured or grungy. It looks too clean and nice. The rain isn't the most appealing either. The color grading needs some work as well. It looks a bit over the top, and often times many shots are either too dark or too bright. The Teal and Orange filter isn't in any way subtle, and the overuse of the effect in Youtube videos makes them more obvious, and it's easy to tell what editor you are using. Not that I think FCPX can have great results, but many title sequences and filters are amateurish unless you tone them done and make them more subtle. That grade doesn't fit the film anyway. Perhaps something more desaturated, or maybe just a light color correct. The surroundings look bleak enough. The opening voiceover doesn't work for it. It's both cheap exposition that we didn't need, and the audio is horrible. From the surroundings and music, we already have a sense that we're in a post-apocalypic world. That scene ends abruptly as well. I suggest you cut the title, and the opening sequence. I'd start with 2 seconds of a black screen, and then begin the film around 0:24. The pacing is slow as well. Not that there's anything wrong with slow pacing, but if your film is paced slowly and nothing is going on, there is a problem. There's nothing wrong with slower moving films, but every moment of a film should be development of characters or tone and/or reveal of information that moves the story forward. This stood still, if that makes sense. The auto exposure, as Baoliun mentioned, is a problem as well. The stabilization effect is also obvious in a film shots. Framing was awkward as well.
As far as story goes, nothing happened. It was just wandering around. We don't know what happened, why it happened, and who caused it. Actually, that's not even important. There was know reflection upon life before this event. It just happens. There's no emotion to it either. The character is so robotic, it just... I don't know. The lack of story and emotion is ultimately what really made the film weak, in my opinion.
Just some recommendations:
Learn more about screenwriting
Get feedback on scripts on screenwriting forums or on IndieTalk.
Get actors and people to work in your projects.
Learn more about framing.
Practice color grading and correction.
Start in as late as possible, end as quickly as possible.
Don't have abrupt transitions and fades.
Anyway, I'm going to watch off to watch Oyster.