Really great atmosphere. Love the space ambience, the subtle ship sound effects along with your footsteps really do set the mood. Then, of course, there is the Imposter sneaking up on you more and more as the game progresses. Did you do all these SFX yourself? If so, I'd love to know how you did it!
I think you've used the black-and-white limitation well, and I also think this game would do really well in a horror themed jam (like I said the mood is great).
Solid game overall, really enjoyed it!