Shadow Warrior was released by 3D Realms in 1997, following in the wake of the wildly successful Duke Nukem 3D. Intended as a spiritual successor to Duke 3D, Shadow Warrior also used the Build Engine and featured an arsenal of over-the-top weapons, hordes of monstrous enemies to violently dispatch, discreet keycard-ladden maze levels, a wise-cracking protagonist, and a crude sense of humor. Despite having more content than Duke Nukem 3D, including more enemies, weapons, levels, and technological features (like drivable vehicles), Shadow Warrior never achieved remotely close to the same success or enduring legacy as Duke Nukem 3D. Aside from a couple of expansion packs (see Expansion Packs section below), no subsequent Shadow Warrior games have been made.
Shadow Warrior is divided into two episodes: Enter the Wang, comprising the first four levels, which was released as the shareware version of the game, and Code of Honor, comprising the subsequent 18 levels, which together with the first episode forms the registered version of the game.
Lo Wang, the game's protagonist, has been a master ninja assassin for 20 years, earning him the distinction of shadow warrior. Shadow warriors are the best of the best, and Lo Wang was the best of the shadow warriors. Every top company in Japan had a shadow warrior... a protector, a negotiator, a cleaner.
Lo Wang worked for Zilla Enterprises, a multi-industry company with control in every major industry, but as he discovered Master Zilla's demonic scheme to rule Japan, using creatures summoned from the dark side, Lo Wang quit. Master Zilla soon realized that Wang was too powerful, and unleashed his demonic creations to kill Lo Wang.
-  Fists of Fury - Delivers rapid punches to the face or groin.
-  Katana - A powerful close range weapon capable of slashing enemies in half.
-  Shuriken (99) - Standard issue ninja throwing stars. Each shot consumes three ammo. Used shurikens can be retrieved from walls. As a result of a British law banning the use of nunchuks, shuriken, or butterfly knives at the time, the European version of Shadow Warrior replaced this weapon with Darts, which function identically to Shuriken.
-  Riotgun (52) - A heavy shotgun that requires reloading after every four shots. Alternate firing mode continuously fires all four shots at once.
-  Uzi (200) - Basic submachine gun that chews through ammo and has low accuracy. Acquiring a second Uzi enables dual wielding.
-  Missile Launcher (50) - Launches missiles (duh). Alternate firing modes include the ability to fire heat seeking missiles after finding a Heatseeking Card as well as a nuke after finding a Nuclear Weapon.
-  Grenade Launcher (50) - A revolving 40mm grenade launcher. The grenades will bounce off of surfaces and detonate on contact with enemies or after 3 seconds of being fired.
-  Sticky Bombs (20) - Proximity explosives that stick to surfaces and become primed after 3 seconds. These will even stick to enemies!
-  Railgun (20) - One of the earliest iterations of this weapon in a first person shooter. It can penetrate multiple targets to devastating effect.
-  Guardian Head (80) - The head of a Guardian which Lo Wang holds impaled on his fingers. By manipulating his fingers, he can select from 3 firing modes: rapid-fire burning projectiles (1 ammo per use), self-orbiting fireballs (20 ammo per use), wave of explosions (10 ammo per use).
-  Ripper Heart (5) - A Ripper's heart which, when squeezed, will summon a mirror ally of Lo Wang armed with a very fast-firing Railgun. The ally will wander the area randomly, attacking all enemies encountered, and expires after 60 seconds.
Note: the number in brackets  is the shortcut key of the weapon; the number in parentheses () is the maximum ammo of the weapon.
- Shurikens - A cluster of shuriken that adds 6 Shuriken ammo.
- Shotshells - A drum of shells that adds 24 ammo for the Riotgun.
- Uzi Clip - A magazine that adds 50 ammo for the Uzi.
- Missiles - A pack of missiles that adds 5 ammo for the Missile Launcher.
- Heatseeking Card - Enables alternate fire mode for the Missile Launcher which adds a heatseeking effect to the next 5 missiles fired.
- Nuclear Bomb - Enables alternate firing mode for the Missile Launcher allowing the launch of one nuclear Missile. The nuclear missile is selectable by pressing the rocket launcher key, after which a countdown begins before the missile may be launched. Everyone with line of sight of the point of impact sustains incredible damage.
- Grenade Rounds - A brown box of grenades that adds 8 ammo for the Grenade Launcher.
- Sticky Bombs - a green box of sticky bombs that adds 5 Sticky Bomb ammo.
- Railgun Rods - A pack of 5 ammo for the Railgun.
- Guardian Head - A severed Guardian's head that adds 30 Guardian Head ammo.
- Ripper Heart - A Ripper's still-beating heart that adds 1 Ripper Heart ammo.
- Health pack - Replenishes 20 health up to 100 maximum.
- Fortune Cookie - Adds 50 Health up to 200 maximum.
- Black Armor - Adds 50 armor up to 50 maximum.
- Red Armor - Adds 100 armor up to 100 maximum.
- Ancient Keys: Bronze, Silver, Gold, Red.
- Keycard: Blue, Red, Yellow, Green.
Each key or keycard will unlock all doors in the current map of the corresponding color. Keys are not lost after use, but cannot be carried beyond the map in which they are found.
- Portable Medkit - Tops off Lo Wang's health to 100 HP until 100 HP of total healing has occurred and is then used up.
- Smoke Bomb - Turns Lo Wang invisible for 60 seconds.
- Repair Toolkit - Repairs damaged vehicles, allowing Lo Wang to drive them and/or fire their weapons, if applicable.
- Caltrops - Produces 3 caltrops which damage anyone who steps on them.
- Flash Bomb - Blinds all enemies in the area for 30 seconds.
- Gas Grenade - Produces a cloud of toxic gas that damages anyone in the area. Expires after 30 seconds.
- Nightvision Goggles - Causes all enemies to be illuminated in bright green regardless of ambient illumination or their own personal cloaking. Expires after 60 seconds of total use; can be toggled on and off at will.
- Brown Evil Ninja - armed with Uzis and Shurikens; low health.
- Red Evil Ninja - armed with Uzis and a Missile Launcher; low health.
- Shadow Ninja - armed with a Guardian Head and Flash Bombs; medium health.
- Orange Ninja - armed with a Missile Launcher with Heatseeking Card; medium health.
- Gray Ninja - armed with a Grenade Launcher; medium health.
- Coolies - A green zombie toting a box of explosives who will attempt to suicidally run into Lo Wang and blow him up. Coolies will often spawn a Coolie Ghost after being killed without being gibbed.
- Coolie Ghost - Can temporarily turn invisible as well as shoot small fireballs.
- Baby Ripper - Small black creatures that can cling to walls and shoot small green fireballs.
- Ripper - Grey demonic gorillas that run fast and will attempt leap attacks.
- Giant Ripper - Brown demonic gorillas that can take a substantial amount of punishment while relentlessly trying to slash Lo Wang.
- Koi - Piranha-like fish that attack in schools, but inflict low damage. They are mostly an indirect danger, as fighting them may distract Lo Wang long enough for him to run out of air while underwater and drown.
- Hornet - More irritating than dangerous. They often attack in swarms, but die in one hit from any weapon.
- Bunny - Just a harmless bunny.
- Guardian - A green demon that will shoot bursts of fireballs and may drop a Guardian Head when killed.
- Assassin - A scantily-clad female ninja who can fire crossbow bolts and throw Sticky Bombs. They often attack in teams.
- Sumo - A massive Sumo wrestler who shakes the ground with his steps and can clap his hands to cause temporary damage over time. After dying, he leaves a toxic flatus comparable to a Gas Grenade.
- Serpent God - The first (and second) boss of the game, a fast-moving four-armed naga that can shooting bursts of green fireballs and has lots of health.
- Zilla - Cyber-robo-samurai-archvillain.
Before the release of Shadow Warrior, 3D Realms started working on 3 expansion packs for the game, however the disappointing sales made them drop the projects.
Two of the three expansion packs can now be downloaded free of charge.