Duke Nukem: Manhattan Project is the fourth entry in the Duke Nukem franchise. It's a sidescrolling platformer, somewhat in style of the first two Duke Nukem games, developed by Sunstorm Interactive and published by ARUSH Entertainment in 2002.

Set after the events of Duke Nukem 3D, Duke faces another Mad Scientist, Mech Morphix, and his army of mutants and robots. Morphix wants to use a radioactive slime called G.L.O.P.P. to mutate insects and other species into giant monstrousness.

Manhattan contains the same side-scrolling gameplay of the first two games, but with the environment itself constructed in 3D, producing an interesting 2.5D hybrid of the earlier games, plus Duke's attitude and mannerisms from Duke Nukem 3D.

A port of this game was released for Xbox Live Arcade in 2010, made directly by 3DRealms.

Followed by the infamous Duke Nukem Forever.

This game shows examples of:

• Added Alliterative Appeal: The episode titles: Rooftop Rebellion, Chinatown Chiller, Metro Madness, Unholy Underworld, Fearsome Factory, Tanker Trouble, Deviant Drilling and Orbital Oblivion.
• Big Applesauce: In contrast to 3D being set around LA, the action moves this time to New York City.
  "New York... If I can kill them here, I can kill them anywhere!"
  "Time to de-worm the Big Apple!"
• Bottomless Magazines: The BFG you get for completing the game on Hard level has infinite ammo, as do all your weapons in the secret boss battle you get for completing the game on all three difficulty levels.
• Breaking the Fourth Wall:
  • After freeing a babe strapped to a mutant bomb:
    "You must be 18 or older to ride."
  • A lampshade by Duke, after freeing a babe:
    "This is why they have games named after me."
• The Coconut Effect: In the (initially mostly dark) Fearsome Factory level, when the lights switch on, they do so with a loud "THUNK".
• Double Jump: A key gameplay mechanic. Many areas and secrets require jumping at the peak of a previous jump to reach. You can't jump if you're descending.
• Dual Wielding: The gator grunts dual wield pistols.
• Evil Is Not Well-Lit: The G.L.O.P.P. factory levels.
  "Jeez, you'd think Morphix could afford a few light bulbs."
• Exploding Barrels: They're everywhere, mostly placed near breakable doors, and come in many varieties, from explosive and GLOPP barrels to explosive boxes.
• Fake Difficulty: Instant kill spikes that can kill Duke despite not visibly touching him start appearing halfway through the game.
• Fembot: The Femmechs are female-shaped robot dominatrixes holding a leash.
• Frictionless Ice: Featured on "Tanker Trouble".
  "I don't remember buying tickets for Mutants On Ice"
• Fun with Acronyms: G.L.O.P.P. stands for Gluon Liquid Omega-Phased Plasma.
• Guide Dang It!: There's a secret boss battle, accessible during the last part of the last mission, but only with requirements such as collecting every Nuke in every difficulty level, then collecting them all in Hard difficulty and going to a specific place in the last part of the last level.
• High-Altitude Battle: Several of the levels such as all three parts of "Rooftop Rebellion" take place among rooftops. Falling from them equals death for the Duke.
• Inconveniently-Placed Conveyor Belt: The path to the Red Card in the second part of "Rooftop Rebellion" requires you to go through a series of conveyor belts with boxes falling onto them; of course, these boxes are lethal for the Duke.
• Inexplicable Treasure Chests: The game puts ammo and health (and sometimes Nukes) in ordinary-looking crates and barrels.
• Innocent Bystander: Across all parts of all levels there are women strapped to GLOPP bombs that must be defused. The defusal is required in order to end a level.
• King Mook: Except for the helicopter in "Rooftop Rebellion", the giant Queen Roach in "Unholy Underworld", and the final boss, all the game's level bosses are simply more powerful versions of standard enemies:
  • "Chinatown Chiller" has the Gator Grunt, the owner of Club Ming, who's a more powerful Gatoroid.
  • "Metro Mayhem" has a Roachoid Boss.
  • "Fearsome Factory" has a Ratoid Boss.
  • "Tanker Trouble" has a Mutated Fly.
  • "Deviant Drilling" has a Fem-Mech.
• Lightning Gun: The secret X=3000 Thunder, obtained by collecting all the Nukes in Hard difficulty, targets automatically any objective on the screen and rumbles in the background when Duke is just holding it.
• Lock and Key Puzzle: Every part has a forcefield door that must be unlocked with a keycard. Duke lampshades this by openly complaining about looking for keys.
• Ludicrous Gibs: The game has its own fair share. Pull off the right kind of kick and you can gib the organic enemies in the game without anything explosive. Quite a few of Duke's deaths also qualify.
• Made of Explodium: Morphix's robots will blow up if hit with anything that would normally gib a mutant, including the aforementioned kick.
• No OSHA Compliance: The "Fearsome Factory" episode. Lampshaded by Duke:
  "Seems like Morphix puts worker safety first... right after everything else."
  "Something tells me this won't pass any safety inspections."
• One-Hit Kill: It's possible to terminate the Pig Cops by Goomba Stomping them.
• Pre-Asskicking One-Liner: Duke has his share of quips here:
  • Killing a giant mutant roach in the subway:
    "Mimic that!"
  • Before the first boss battle (against Morphix in a helicopter)
    "There're only two ways this can end. And in both of 'em, you die!"
• Punny Name: Some of the shop names in "Chinatown Chiller", such as "Wan-Sum" (liquor)^note From Duke's catchphrase "Who wants some?", and "Long Fat Pow" (fireworks).
• Rise to the Challenge: The fourth boss fight against the Queen Cockroach has her destroying all the wagons of the subway train.
• Rescue Sex: As the ending says:
  "The Big Apple and the world is saved. Mech Morphix space station will splashdown somewhere in the South Pacific.
  
  What's Duke to do? Well, let's just say that all those babes he saved from the bombs are ready to show Duke just how much they appreaciate him. Manhattan Project has just begun..."
• Score Screen: A similar stats screen to Duke 3D with the game's version of "Grabbag" playing on the background showing how many enemies Duke killed, how many secrets he found, and how many nukes he collected.
• Shareware: The first episode, "Rooftop Rebellion", was available as a free download.
• Shout-Out: Check the page.
• Superboss: If you collect every Nuke on Hard mode, play through the final level again, and then take an unmarked path just before the chamber Morphix is fought in, you get to fight Wozma, a giant ball of GLOPP that is able to distort space and time around itself.
• Super Drowning Skills: Unlike its predecessors, it's played straight here. Water won't hurt you, unless you're trying to swim.
• Suspiciously Similar Substitute: Mech Morphix was originally supposed to be Dr. Proton, the villain of the first Duke Nukem game (as well as the original iteration of Duke Nukem Forever), but was changed to be an entirely different character during development. The two characters look virtually identical.
• Take That!: The intro to "Deviant Drilling":
  "Morphix and his GLOPP reign are going down faster than Enron."
• Taking You with Me: The Gator Grunt Boss will blow himself.
  "The fortune cookie didn't say anything about this! You will never take me alive! If this doesn't kill you, the bombs in the subway will!"
• Tempting Fate: After fighting the Queen Cockroach, the underground base starts to collapse, and a boulder falls on her. Then, Duke takes a train and escapes from her...
  "Ah, just in time." [she reappears again - cue Boss Battle] "Maybe I spoke too soon."
• Underground Level:
  • Metro Mayhem and Unholy Underworld take place in a subway station.
  • Fearsome Factory takes place in a mine factory.
• Whip of Dominance: The Fem-Mechs are Dominatrix themed female androids that are dressed the part, including using a whip as their primary weapon. Downplayed with their stronger variants and the boss version, who don't have their human skin and are simply robotic skeletons, but still keep their domineering dialogue and wield electric whips.

"I am the king of the world, baby."