Back to the Future: The Game - 30th Anniversary Edition

At the very end of the episode "Double Vision", after having a conversation with Doc on the ledge of the court house, a statue falls off the ledge, taking Doc with it. Doc is hanging upside down tied to the statue. Interact with Doc to ask him if he has anything useful. He will then drop the spray bottle that dissolves clothing. Slide down the opposite rope from Doc and pick up the bottle. Then equip the bottle and spray the rope you came down to release it from the statue, allowing you to swing on it. Then re-enter the courthouse doors. When you come out on the ledge, slide down the again. Once halfway down the rope, highlight Doc so you can interact with him quickly. Then began swinging the rope towards Doc, then away from Doc to gain momentum. Alternate directions until you get close, then interact with him. You will grab him and then another pause in the action will allow you to equip the spray bottle again. Use it on Doc, spraying his pants, and freeing him from the tangled rope.

Here's a complete Walkthrough of Episode 4, with all missable Achievements.