Nice entry, cool concept as well! We were also playing with the idea of making a hospital game with a blood stealing vampire (as you mentioned in your game description.
As some of the other commenters already said some sound would have really been nice. What worked for me in the past was generating some quick sound effects on here: https://sfxr.me/
I probably missed it, but was there some sort of way to tell which guests had blood A type, or was it more of a trial and error thing?