Unlike the surrounding landscape, which is a collection of Monty Mole Mole Holes, Fort Banzai is built entirely aboveground. The walls bristle with long-range weaponry. Any attempt at opening the door directly will result in you being blown to smithereens. Bowser Jr. can throw Paint at the door, causing the weapons to target that movement. The door is then the target of detonation, and you can walk through a smoking crater.
Fort Banzai is filled with blasters for Bullet Bills, Banzai Bills, and even King Bills. These blasters are manned by Monty Moles, who will rotate the cannons if you pass them by. Since Shadow Mario cannot affect Bullets with his Shadow Balls, the Monty Moles are your target. The Iron Goombas are standing on top of triple-barreled Bill Blasters. These can be clogged with well-aimed Paint, allowing the opening for a Shadow Ball.
After Major Burrows is defeated, the Monty Moles will all run for their holes as the Blasters go haywire. Well-timed-and-placed ducking allows you to escape through holes made by the Bills. Once outside, it is vital that you do not enter the Mole Holes. Seconds after your escape, the Holes will be struck by Bills. The best way to survive is to run like heck. The fort will eventually blow itself to pieces with an echo sounding remarkably like "BANZAI!!!!!!!!!"
- Seen from the fort, Area 5 looks like it has been nuked, which foreshadows its self-destruct method.