As others have said this game is extremely aesthetically pleasing and the addition of music and SFX would make it sooo creepy. The design of the environment of the maps is really well too!
I'm not sure if I completed the game or not, I basically explored the ship a few times until the "sister" came to get me. There may be a bug but nothing happens when she get me (other than I can't see where I'm walking very well).
This is the beginning of the kind of games I love and would buy for a full version. Great job :}