- Go to Zilla Enterprises, blow wood boxes by shooting gas bottles, you can now access airvent which is a secret place
- Start point, hit Gong : message "maybe next time"
- Outside on street, the truck reads "Hertel Co." (Karlheinz Hertel is a great beta-tester)
- In train-station, if you open one of the green doors (or ghost through) you'll see 2 messages . "Where did you find a green key !!" & "You have no honor"
- Street, right of Takagy building, there's a sign "Duke4ever : coming when it's done (but hopefully before 2000)"
- In laundry, in corridor, left wall: "there is another way" (which is the secret place)
- In cinema, movie : "The Smoking Cigar, starring Billy the Clint & Monica Whisky"
- In cinema, blow screen: text "Played Duke Nukem 3D too much ? hehe"