Each time you roll the dice, you set aside (or keep track of, on paper) all of the brains you collected. You also set aside any shotgun blasts. If you get shot by your intended victims too many times you lose the brains you’ve accumulated on that roll. So if I rolled a few times and ended up with five brains and two shotgun blasts, I could either choose to keep rolling (and possibly lose all of my brains), or bank my brains and pass the turn to the next player. It’s simple fun that’s easy to teach and quick to play.