The Exterior is not a floor by its own right but is a location you access by defeating The Last Dragun. When you defeat the boss you drop down on a parachute and are presented with the panorama of The Gungeon.
While the area is mostly empty it has two objects in it
- A bullet mound to the left of the dropsite. Normally It's too big to cross, but it you buy the Bait Worm the mound appears to be cut in half letting you meet up with Super Space Turtle on a jetski and access the secret bossfight. More info at the Glocktopus page.
- The ship of the Gungeoneers. When you interact with it while playing as The Pilot, The Marine, The Hunter, The Convict or The Robot you enter the ship and have to interact with the seat (unique for every character) to escape The Gungeon and fly away. If you are playing as The Bullet or The Cultist, the ship flies away as soon as you approach it leaving you behind.