Find all 3 helmets in the SP campaign
There are three “helmets” you can find throughout the campaign and the video above will show their locations. The first one is the Master Chief helmet which is the easiest to spot, while the other two are hidden away in more inconspicuous places. Watch the video above for their locations.
Listen to All Phone Messages
There are 14 phones that are scattered about the single player campaign. The phones are pretty useless as they have nothing to do with anything and the messages they play aren’t all that interesting either. Below are the levels and locations for each.
When you are your penthouse, head to the washroom and find the first phone hanging on the wall beside the toilet.
The Duke Dome
After you ride the crane, you will need to break a lock to go through a fence. Once through, enter the construction trailer and the phone will be inside.
Duke Nukem's Titty City
The first phone in the strip bar is on the desk to the right, after you talk to the first stripper.
The next phone is in the office at the top of the stairs, on the desk, beside the monitor.
The third is in Duke’s office- the one that needs the code 4768 to enter.
The final phone is on the desk of the woman who is outside of the Champagne Room.
The Duke Burger
When you stand up at the start of this level, turn around and head to the far end where there is a desk with a bunch of Duke figures on the wall. The phone is on the desk there.
The Mighty Foot
You can find the two phones of this level In the construction trailer building where you grab the first fuel can. They are opposite sides of the room of each other.
This phone is found on the desk in the same room as the calendar for the “I Need a Date” achievement/trophy.
At the beginning of the level, you will step out the elevator. Head to the left and around the corner, beside a water fountain will be the phone hanging on the wall.
The first of this level is found in a room you come to where you need to break 4 boxes that are in a door way to continue on.
The next is found in a room with a whiteboard message about beer, that you drop into after you push the scaffolding with wheels.
The final phone of the game is in the room with the electrified water. Head to the far side of the room and then go through the corridor and up the stairs to the second floor. When you reach the top of the stairs, the phone will be right in front of you.
Complete the SP campaign on Hard Difficulty
Just as it says. But if you are going to play on hard, you might as well go balls out and just suffer through insane.
Unlock the secret closet at the end of the Forkstop
At the end of Forkstop part 2, you will come to a room that has another forklift on a lift and a room full of enemies. Once the enemies are wiped out, use the forklift and head to the opposite wall of where the platform is that the green button lowers. Raise the forks and hop up to the balcony and head down the hallway to find a barrel with a heart on it. Take the barrel and hop down; cross the room and then jump up on to the platform you lowered. Carry the barrel down the hallway to the left and place it on the heart on the floor. When you do there will be a reference to cake – another reason this game needs to die- and the door to a supply room will open giving you this achievement/trophy.