This is a grim little masterpiece. The graphics seem unsophisticated at first, but in fact the color palette perfectly suits the bleakness of the story.
The audio is outstanding. From the shell reloading (agonizingly slow) to the flashback audio (which I won't spoil) to the grotesque wails of the mutants, everything combines to create an atmosphere of horror and despair.
The implementation of the jam focus is thematically appropriate without overburdening the gameplay.
Finding enough resources seems impossible at first. It's technically not, but thematically, this is precisely the point, and it's driven home effectively.
It's hard to find improvements to recommend, but in the spirit of constructive feedback, I felt that the collision wasn't always quite right for certain objects. I also felt that it should be possible to fire over certain obstacles.