Here are some things you should do before The Witcher 3 On Thin ice: • Save the game. At this point, you probably already had to learn -either the easy or hard way- that you should create a save as often as possible. You are about to head into one of the final quests, so save your game. • Complete the sidequest Reason of State. It can impact the outcome of the final quest, or rather, make a specific ending inaccessible. Make sure that one is cleared before you proceed.