Does anyone have in-depth information on heart placement? Kidney's and Brain are pretty lenient, but the heart can sometimes be frustrating.

The heart has to face at certain angles for it to register. In the surgical theatre and the ambulance, when you open the heart container it's already facing the way it should. So all you have to do is grab and drop it straight down once you've made Bob's heart stop beating. In space, however, the heart slowly rotates as it's floating up. So if you push in the new heart and it doesn't work, try turn it 90 or even 180 degrees and see if it works.