Secret 1: Beside the geisha
In the first corridor of the sushi restaurant, locate the section of the wall to the left of the red geisha statue by the entrance. This is a faux wall; jumping through the wall will reveal the first secret.
Secret 2: Exotica poster
In the first corridor of the sushi restaurant, face the "Exotica" poster with a bikini-clad woman on the wall. While pointing at the woman's crotch, press the "use"/"open" key to reveal a secret compartment with a Shrinker inside. This will not work unless the player is pointing specifically at the woman's crotch.
Secret 3: Handprint on the chalkboard
In the first corridor of the sushi restaurant, walk to the end of the corridor. Open the chalkboard with a bloody handprint on it. Physically jump into the compartment to unlock the secret.
Secret 4: Crack in the dining room wall
In the first corridor of the sushi restaurant, there is a row of traditional Japanese dining rooms along the left wall. Enter the rightmost dining room. In the wall on the right, there is a crack. Blast through the crack with explosives to discover the fourth secret.
Secret 5: Handprint beside the sushi bar
In the room with the sushi bar (where trays of food are carried along a flooded conveyor belt), walk behind the wall to the right of the sushi bar. On the wall, there is a bloody handprint. Pressing the "use"/"open" key on the bloody handprint will open a nearby wall, revealing a secret compartment with a Freezethrower inside.
Secret 6: Back wall of the cupboard
In the room with the sushi bar (where trays of food are carried along a flooded conveyor belt), walk behind the wall to the right of the sushi bar. Open the cupboard in the wall, and climb inside. Press the "use"/"open" key while facing the left wall of the cupboard to reveal a secret behind the cupboard.
Secret 7: Wine cabinet
In the kitchen, you will see what looks like a wine cabinet. Open it for two crates of RPG ammo and the last secret.
The following hidden compartments are not counted as secrets:
- On the roof at the beginning of the level, open the middle window on the right to reveal a Devastator inside.
- Upon entering the sushi restaurant, walk near the sign on the right, and a wall should have opened in the opposite corner behind you.
- Inside the sushi restaurant, go into the first room on the left. Open the wall on the left to find a Jetpack inside.
- When you first jump off the roof at the start of the level and head up the ramp to the restaurant, do not go into the restaurant. Instead, jump over the small wall on the right, and blast through the crack in the wall.
- Past the room with the captive women, enter the room with the cash register and Blue Access Card. Press the "use"/"open" key while facing the cash register. This will open numerous teleporters all over the level. These hidden teleporters are found on most levels of the game and are normally only revealed during multiplayer.
- The level starts with Duke saying "It's time to kick ass and chew bubblegum. And I'm all out of gum." which is a reference to the 1988 film They Live where Nada says "I have come here to chew bubblegum and kick ass. And I'm all out of bubblegum."
- The cash register on this level features Visa and MasterCard logos.
- If you use the microphone in the karaoke bar, Duke will sing "Born to be wiiiiild!" which is a reference to Steppenwolf's famous song of the same title. The television screen is also referring to this song.
- In the corner beneath the Turret inside the restaurant, a hidden message on the wall reads, "Push her button." This is a clue for discovering Secret 2 above.
- Inside the cupboard beneath the vent in the room with the sushi bar, a faint message on the wall reads, "Push me," a clue for discovering Secret 5 above.
- This requires the DNCLIP cheat: At the end of the level, there is a crack in the wall, through which you can see the second level of this episode. If you walk through this wall and explore the outer area, you will come across a message: "NO ONE SHOULD BE HERE - LEVELORD."