These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Crosses the Line Twice: The line gets crossed when you accidentally get the drill stuck in the patient. It gets crossed again while you flail about trying to get it out as it whips around by its drill bit.
This phone call:
Nigel's friend: A'right Nigel, I've been wondering what going on with that mystery meat you've been sellin' me. Half my customers think it's absolutely lovely, the other half have been puking their guts up! Not that I mind, mind you; I just put it back into the kebabs.
It's entirely possible, in the Ambulance Brain Transplant, to have the patient instantly killed by a fire extinguisher to the brain. Less than ten seconds in the surgery.
Game Breaker: The experimental mode with the Razer Hydra controller gives you two hands and a lot more dexterity. If it actually worked for every level, the game would be a lot easier than it's supposed to be.
Guide Dang It: This is very much a trial-and-error game, especially if you're going for A++. The first few times you play the game, it'll be an achievement just getting through the bones, let alone taking out an organ. The kidney surgery is especially bad, requiring no less than five precision cuts just to get the first set of organs out. Deliberately invoked with the alien surgery, which changes the objective on each playthrough and doesn't tell you what's what.
Suspiciously Similar Song: The initial segment of the track "Unidentified Flying Organ" (Which plays during the alien surgery) sounds suspiciously similar to the theme music of the series The X-Files.
That One Level: Ambulance Brain Transplant. Trying to clear out the skull and separate the brain stem while avoiding damage to the most sensitive organ in the game is incredibly frustrating with the constant motion, especially if you're going for A++. Doubly so because, as noted above, the patient can die through no fault of your own. The space version is actually easier because the brain floats up and makes cutting the brain stem a breeze.