The plot idea for this was very interesting. I really liked that, and the writing itself flows in a way that makes it easy, fast, and pleasant to read. But there are many missing elements that could have made this so much better...
I have no idea what I'm looking at... By that, I mean, if you asked me what color hair or eyes a character has, I couldn't tell you. Skin tone? Well, I could make assumptions, but I'm not really sure. And when the doors are opened onto the ruined land, what do we see? There are scant mentions of a cloudy, dark sky and an "ashy" ground, but what else? Tree stumps? Rocks?
There is *some* description, but not enough. The world and characters could have used a good deal more fleshing out. I wanted to be more concerned about the characters, but I knew so little about them that it was difficult to form any kind of attachment to them. With a little more description and detail, I'm sure I would have felt more immersed in this world and more concern for the characters and their struggles. Everything felt very rushed. The story isn't long (about 70 pages, I think), but even so, I felt so much was left out as to make too much of it turn empty.
Someone else had mentioned a lack of quotation marks. I found that to be distracting, also. There are some places in which there are quotation marks, but it isn't made clear who is saying what, and when you do know who's doing the talking, the quotation marks are absent. If the lack of quotation marks was supposed to represent inner dialog, putting the thoughts into italics would have helped to separate them from the general narrative to make it easier to keep track of what the character is thinking and what the narration is explaining so as not to get jumbled up as to what's what.
Overall, not bad. Needs a little more detail, longer scenes, and more character development, but the writing is pretty good. If you like dark science fiction, it's definitely worth the read.