1. When the level first starts, you can go through the IMF door, or you can go to the other side of the rock canyon. If you jump up on it, and make your way back above where you started, you will see a small, and rather narrow ledge. Follow the ledge around the canyon, and you will come to a cavern. Inside it is a Holoduke and some pipebombs, as well as one of the turrets that was shooting at you when you were at the start (Note: No Turrets are present out here on Piece Of Cake). It can be pretty dark in here, and it is easy to fall off on your way up here.
2. If you go up on the ledge in the start of the level, and walk around on top of where you started the level, you will see a red hand on the wall. Hit it.This will open up a door below you, and behind your initial starting spot in the level. Jump off the ledge, and head in there. Once inside, you will see a red room with an Atomic Health inside. Go in there to claim the second secret of the level.
3. The third secret is in the mess hall area. Once you clear out all the enemies, make your way into the back - you will see a silver door leading to the meat locker. Go in there, and take out an Octabrain in close quarters!. Once you've done that, hit the red hand on the wall. Doing that will open up another room with a forcefield and a computer. Using the computer will give you access to the next room, the one with a Shrink Ray and some armor, as well as the third secret. From here, you can either backtrack to get back to the kitchen, or you can jump into the water here, and swim back to the sink in the kitchen (this is the shorter path).
4. The fourth secret is in the barracks area of the level. There's a bunch of pig cops to take out first. Once you do that, make your way to the bed towards the back of the room that has steroids sitting on it. Stand on the bed, and "use" the wall. The bed will raise into the ceiling, taking you with it. It will reveal a path you can take to get to a door. Open it, and a room will be revealed with a Jetpack and some Devastator ammo.
5. The fifth secret is in the bathroom. Above the sink is a switch that looks like a hand dryer. Flip it, and a compartment will open up above the toilet. Jump up there and head in to get the fifth secret, and a medkit.
6. The sixth secret is the room where you get the red key. Next to the picture of President Washington, there is a computer. If you use the computer, it will open up a door on the other side of the room with a pig cop behind it. Take out the pig cop. Once the pig cop is taken out, go into the room he was in. There is an RPG in there, as well as the sixth secret. The game prints the word "Unlocked" instead of "A Secret Place!" when you go into this secret because it unlocks a secret door on the wall, which connects to the fourth secret area, that was previously locked if you went to secret four first. This is also an easy way to get the fourth secret without needing to fight your way through the barracks at all, and getting both secrets together.
7. The final secret is in the middle of the Get Smart reference (The Sequence where all the doors open towards the end of the level). After the second door, you will see a vent up near the ceiling. Kick or shoot the gate, and head in the vent. There is another gate at the far end, kick it or shoot it and then head out. There's some enemies in here waiting for you; take them out. You will see a switch here. Flip the switch, and it will allow you access to the mine car. Go into the mine car to get the seventh and final secret for this level. While it isn't part of the secret as such, you can also go through the door that says "Under Construction", and make your way past an Assault Commander and a few other enemies to get a Devastator. (Assault Commander is not present in Piece of Cake difficulty)
- The IMF Logo seen at the start of the level is stated to stand for Improbable Mission Facility in the level, but it's an obvious parody of the Impossible Mission Force (Also Abbreviated with IMF) from the Mission: Impossible series and the films.
- The Music that plays in the level closely resembles the Mission: Impossible theme.
- In the room of the red keycard, there are monitors showing something which looks like a comet...but it's not! It is, in fact, a burning fuse! Yes! The same from the '60s TV show "Mission: Impossible".
- Beside the TV in the barracks, there is a magazine with a golden ring on a pink background on it. The inscription reads Moger Roore, which is actually supposed to be Roger Moore, and the golden ring is possibly an allusion to Goldfinger, the third movie in Eon Productions' James Bond series (however, in that movie James Bond was still portrayed by Sean Connery). It could also be a reference to the spy show, "The Saint" and is a halo. "The Saint" also starred Roger Moore.
- In the kitchen, go to the flowing water. Use DNCLIP and follow the flow of the river. You'll eventually come to a small message on the wall, credit to Randall Pitchford: "ARE YOU SMALL OR ARE YOU CHEATING?". Probably cheating :)
- There's a tape recorder in this level and when Duke interacts with it; Duke will say "This tape will self destruct in one second" and it does indeed self-destruct a second after, which is another homage to the Mission: Impossible franchise; it's also quite a nasty surprise for the player as the explosion can take away a good bit of health; so stand clear after interacting with the tape recorder.
- In the briefing room a "Steed" hanger with an umbrella and hat can be seen. This is a reference to the character of John Steed from the old British Show "The Avengers".
- The White Computer Room with the computer mimics the scene in the first Mission Impossible Film where Ethan Hunt (Tom Cruise) was suspended in mid air in the computer room. The player can take a similar approach if they have a jetpack to deal with all the buttons in the area; the reason the player might decide to use a jetpack in this area is to avoid hitting the floor because if they do, it will trigger an alarm and they'll be surrounded by several aliens.
- The sequence of doors near the end of the level is a reference to the opening of the 60's TV Show Get Smart.
- Just after the sequence of doors is a telephone that has "U.N.C.L.E" on it; this is a reference to The Man from U.N.C.L.E. and the lift where the telephone is further references the Get Smart opening as Duke descends it just like in the opening sequence.
- Once arriving in the storage room that requires the Red Key Card, move behind the box in the corner to read a message: "From: Wars of the World Prop Dept. To: O. Wells. Prop #45". This is in reference to the famous radio broadcast of H.G. Wells' The War of the Worlds which told of an invasion from Mars. O. Wells refers to actor Orson Welles who had directed and narrated the famous broadcast in 1938. This crate can be opened to reveal Expander Ammunition; interestingly the firing sound of the Expander is the same sound effect from the 1950s War of the Worlds film by George Pal, used by the Martian Heat-rays. This might be a coincidence however, since a great number of this movie's sound effects have since become stock sound effects that have been reused in a great number of productions (most famously the Star Wars movies).