Duke Nukem II is a platform game and a sequel to Duke Nukem. While giving an interview on TV, the famous muscular hero Duke Nukem is captured by the evil Rigelatins, who intend to use his brain for conquering Earth. Duke easily escapes his prison cell.
Now he has to make his way through four episodes, each one consisting of an assortment of levels with varying graphic design. On his way, Duke has to destroy lots of obstacles and enemies - both Rigelatin forces and apparent local wildlife. Initially, Duke has just a weak laser rifle, but he can also find a flamethrower (which allows him to shoot down to launch himself in the air), a rocket launcher or a far more powerful laser cannon. These stronger weapons, however, have limited ammo.
There are also lots of items to collect: health items such as soda cans or atom power-ups, Duke Nukem merchandise which gives score, keys and access cards that let him pass through locked door or electrical barriers. Duke can also find a rapid fire power-up which lets him shoot faster, a cloaking device which allows him to go through forcefields, and a globe which will give the player a hint when brought to a special pedestal. A lot of items are hidden in boxes of various colors which have to be opened by shooting. Beware, as some boxes do not contain items, but rather a harmful bomb!
On some levels, Duke can find a small spaceship. He can enter it and fly around the level, using the ship’s powerful cannon to mow down everything in his way. However, the ship won’t fit everywhere, so Duke will have to get out of it eventually.