There an easter egg on Kowloon similar to the Ray Gun easter egg.
Here Proof :
And here are the steps to obtain it :
- . After the Interrogation scene ends there is 6 canisters to the front of the player, have the player throw 2 grenades to the back left and right white canisters.
- shoot the remaining 4 canisters on your left and right until you see the smoke come out.
- Run behind and make a left to desk.
- If done correctly the player will see a Black tape sticking out of a cassette player.
- Hold down the "X"(X360) or if on PS3 the "Square" button and the tape will dissappear from the cassette player.
- Go upstairs and clear the room by killing all the enemies.
- When at the rooftop jump to the next floor.
- When Weaver and Clarke open the fridge with the weapons room enter.
- Look at the left and notice there is a cassette player.
- When at the cassette player press the use button and notice the cassatte go in.
- If done correctly notice the tape goes in and makes a weird sound and the game shakes.
- a gun will appear out of the wall and TADA! a Thundergun will appear.