Good, clean, post-apocolyptic fun.

Being picky, I'd complain about the flow of the actual writing. There's little sentence variation and a lot of sentences that just start with 'He.' Good once every four or three, maybe, sentences, but one after another is hard to do well.

Not a bad idea for a prologue, but there's a lot of background information that could make it better. More details on the war itself, I say. The prologue makes it seem more like the story will revolve around Ernie and his findings rather than the war itself.... that is until he's shot.

But reading through your entry, I felt a lack of impact when looking over the war.

I say spice it up. More drama (the shooting could've been bigger... it feels a little weak at the moment... but good way to end it), better sentence variation, and greater background.