Shadowkeep

A 1991 Mac Shareware RPG by Glenn Seemann.

Not to be confused with Shadowkeep, a mid-1980s RPG by Trillium.

This game contains examples of:

 * Cosmic Keystone (The Ankh)
 * Dronejam
 * Experience Points (Subverted; they're only good for Scoring Points)
 * Evil Overlord ("The Evil Overlord")
 * Fumbling the Gauntlet (Do not enter Shadow Keep with your weapon drawn)
 * Healing Potion
 * Hit Points
 * Interchangeable Antimatter Keys ("Magic Keys")
 * Nightmare Fuel (The laughing cartoon demon superimposed over the interface when you die)
 * Plot Coupon (Several)
 * Roaming Enemy (The outdoors is crawling with Giant Spiders, Scary Scorpions, and Goddamned Bats)
 * Shareware (The author requests a "measly ten bucks" if you "don't want to burn in the fires of hell for all eternity")
 * Shoplift and Die (The castle's treasure room)
 * Shout-Out (John, the paper airplane enthusiast)
 * Sword of Plot Advancement (The Black Sword)
 * Trauma Inn
 * Unicorn
 * Universal Poison (Averted; spider and scorpion venom have separate antidotes)
 * Walk It Off
 * We Buy Anything (Averted; a shop will only buy the same sorts of items it sells)
 * When Trees Attack
 * Wide Open Sandbox
 * Wizard Needs Food Badly
 * Ye Olde Butcherede Englishe