This is heavy! I could expect that from the theme like this, but man, that last level took a surprising turn. So yeah, when it comes to the atmosphere you did it.
Same goes for the sound. Having made one game featuring a helicopter I appreciate that you kept the sound quiet, bringing the breathing to the front. Most of the jam games have sound effects. Some have music. Your has a soundscape. Kudos.
The graphics are good. If I were to nitpick I'd say that no matter which direction you move the flight stick moves the same :)
Returning to the theme. It was really cool that you went with this interpretation. You could almost feel the guilt. When I discovered that there's no point in going to the buildings that have less than half health, because there will be no time to save it I started to try to save the "heathier" buildings. Then, the theme hit me even stronger. I started my comment with this, but it's worth to say again. You really did a good job on the atmosphere.