Inspired by Berzerk, Shamus, a 21st-century robo-detective, must travel a maze of 128 screens to find and destroy the evil Shadow (himself an Expy of Evil Otto). He must find the right keys to unlock doors, collecting "mysteries" that give points or extra lives (or summon the Shadow), and defeat many, many enemies. You're equipped with an unlimited supply of "Ion-SHIVs", laser throwing knives that can vaporize nearly any enemy in your path.
Followed by a very hard-to-find sequel, Shamus: Case II.
- Coat, Hat, Mask: That'd be you.
- Deadly Walls: Touch any wall and YOU ARE DEAD.
- Everything Trying to Kill You: Everything, including the walls.
- Expy: The Shadow is one, of Berzerk's Evil Otto.
- Fun with Acronyms: Your "Ion-SHIV", a.k.a. the "Ion Short High-Intensity Vaporizer".
- Hitbox Dissonance: In the Atari and Color Computer versions, it is entirely possible for horizontal enemy bullets to pass safely through the space between the hat and the head.
- Knife Nut: With laser knives, no less.
- Ninja Pirate Zombie Robot: You're a robotic detective.
- One-Hit-Point Wonder
- Real Song Theme Tune: The opening is an 8-bit ditty of Charles Gounod's "Funeral March of a Marionette", also known as the Alfred Hitchcock Presents theme.
- Except on the Color Computer where it was instead Edvard Grieg's iconic "In the Hall of the Mountain King".
- Spiritual Successor: Of Berzerk.
- Stalked by the Bell: The Shadow. If you don't exit a room fast enough, the Shadow will chase you out.