Split Splat! Achievement
Take out two Splitter spawns with a single shot.
A splitter is an enemy who physically splits into two enemies or more, creating a clone of itself. It basically multiplies. What you need to do is kill two at once with one shot. The first time you see this enemy is the perfect time to get the achievement. When going for the item near the train tracks during the "Find items for rewriting reality" objective, this enemy will jump out from the door of a building you are supposed to enter. The game will inform you of this new enemy. Shine your light on it and to make it easier, let it split again. Now you will have 4 enemies to shoot at. Take your shots. If your achievement doesn't unlock, just reload your last checkpoint. It will put you right in front of the building again. You can always get it later, but it's nice to get it out of the way here.