A bit confusing, and when you finish with the blood it's not very clear what you're supposed to do, "find the shifter", but I think i clicked on the shifter by mistake and did not know what I was doing after, The audio is pretty good, some animations when taking blood or some higher risks for taking it from the shifter?
The interactions where not clear, you had an audio feedback on taking blood, but some visual would be a good addition.
The blood on the machine just shows red or green, are they ment to be something else, was it also suposed to allow me to entry two of the same? As far as I see it, you could just make a bit more polish on the information to pass to the player and then it would be a much better experience.