Duke!ZONE II introduces three original episodes by Simply Silly Software. Although removed from the Kill-A-Ton Collection version, the original Duke!ZONE II also included the 500 user maps from the first Duke!ZONE.
Some of the game's assets were later repurposed in Duke: Nuclear Winter by the same developers.
The maps in Duke!ZONE II have been criticized for their mediocre design and unfair difficulty. Another common criticism of the expansion pack is that, unlike other expansion packs for Duke Nukem 3D, Duke!ZONE II does not feature any new graphics, enemies, weapons, or items.
Duke!ZONE II contains three new episodes, with seven levels in each:
- Arctic Assault - "Duke must shoot his way through an urban arctic wasteland - it's cold."
- Alien Abby - "Duke battles his way through underground passages, hidden switches, trap doors, and more adrenaline-pumping excitement."
- Monkey Shines - "Duke shoots his way through canyons, a funky fun house, a hip bar and a toxic chemical processing plant - just to name a few - and the last level, 'No where to run' is jam-packed with monsters and none too easy."
A list of the levels can be conferred below:
The level "4 Way Stop" can only be accessed via cheats or command line arguments, as it is not linked to any secret exits. It is unclear if whether this is a design flaw. "4 Way Stop" was later repurposed in the map "Santa Match" for Duke: Nuclear Winter.
This add-on features a few Easter eggs:
- The levels Graveyard Shift, The Abby, and Dining Out feature edited versions of Duke Nukem's sprites as part of the scenery.
- The corpse of Doomguy can be found at the beginning of Graveyard Shift, above a grave.
- The robotic arm from The Terminator can be found in the level Dining Out.
- The level Cop City has two unique NPCs: a woman inside of a whirlpool and another woman chained to the ceiling. The chained woman was later featured in Duke: Nuclear Winter.