Creative use of the title! The depth crawl with increasingly menacing/eery events has a potential to feel like Heart of Darkness or Apocalypse Now. I imagine this would work well as a drop in adventure with little preparation.

Felt very 40k, but touching specifically on disparate technology levels between worlds, have expected when players found the ship that it would get blown up from orbit. Nice survival and search framework, I think the days spent searching adding to the roll is a good touch for an abstracted search so you aren’t just stuck not finding anything for ever because of bad rolls.

I love the idea of crawling a salt marsh looking for wreckage, while avoiding potentially hostile natives. It has the potential to be a tense, brutal experience if played right. I would have loved to hear more on the chain gang and what that means for the PCs; the possibility that the PCs are under the watch of a harsh warden or technological restrictions -- And might see this as a chance to give the Law the slip -- adds cool additional dimension.

You've done a great job laying out a march crawl here with enough specific mechanics to make it interesting and very playable. I think your map could be more useful - if both main areas of interest are in the middle of the map it's probably not scaled (or designed) appropriately. Zooming in to give better detail to the core adventure area might be useful, or spreading out the two areas of interest so that the entire map is more obviously playable.

Great cover. I didn't know Pulp-O-Mizer existed until now!