I really like your theme, and your extreme focus on one particular scenario - that's the best way to make ultralight games like this, in my opinion.
However, I do think that scenario's a bit underdeveloped. A set of locations provided through a table (or a depthcrawl, given that the only important movement is towards/away from the front) would help reinforce that focus, and make the game much faster to prep.
Also, I wish that instead of page 4's list of common items, you had a table (either to roll on for PCs during character creation, or just to generally use for rewards).