Delivertree

One day during a stroll, you've discovered upon and undelivered letter on the ground. Being the good samaritan that you are, you decide to finish the job. Only one obstacle stand in your way: a maze of identically-marked doors and hallways.

Perhaps those goats can help you narrow down the right mailbox. They can be slow at times, and not give much help individually, but with many of them together and the awesome reception of your phone, you'll work this out.

← → - Move
↑ ↓ - Enter door, activate hint goat