Really loved this one! Sci-fi themed action/survival horror games are my jam! The monster encounter was damn scary and the noises it makes when it roams the ship really kept me on the edge. I beat it on easy, to compensate for the fact that I needed to Alt-Tab out of the game every 20 seconds to look at the map, because holy damn, it's impossible to locate where to go without it. I strongly recommend you put it in the game in case you haven't planned to do so.
That's the only major issue I'd say deserve a priority fix, because the rest of the game was top notch! I'm fond of the low quality graphics you went for, reminds me of System Shock 2, and the stealth mechanic kept me crawling in the ship like a scared animal watching out for every suspicious noise. The story line was well explained and executed and I always knew what I had to do. And the fact that you get to obliterate the monster at the end was really cool, although it could be made more climactic if you triggered the monster to come to you as soon as you obtain the big gun!
Awesome game overall, well done!