Far Cry 5 let’s you unlock a secret easter egg ending right at the beginning of the game. Just like previous Far Cry games this Alternate Ending is triggered by the players actions, or lack there of in this case.
After the first cut-scene your character enters the church and is about to make an arrest. If you refuse to make the arrest and don’t press the button you will exit the church again, finish the story and the credits roll.
Simple but fun way to see a secret conclusion of the story.