Mission: Mainframe (1987, DOS / Jerry Plemons and Brian Shankman)

Author(s): Jerry Plemons and Brian Shankman. Released 1987-08-29 as shareware at $15, later circulated as public domain.

Sources: The CRPG Addict: Game 37 (1987) and Won!* (mechanics, from a full playthrough) · Internet Archive: msdos_Mission_-_Mainframe_1987 · myabandonware.com · DOSGames · old-games.com · PhotoGabble

Category: inspiration, hacking sim. Captured 2026-07-29 to close the last uncaptured gameplay source on the intrusion chain, ahead of designing the ICE Breaker loop. Serves: ICE Breaker, Tunnel Rat (assigned by Josh; see cart map)

The premise

A corporation’s mainframe goes mad after an electrical disturbance, takes control of its operator, and begins influencing the other employees. The operator’s job is to climb the building, locate the mainframe, defeat the operator, and get back to the lobby alive. The win condition is stated as returning to the lobby with knowledge of the mainframe’s location, so the payload is information rather than a kill.

Mechanics

The building is the dungeon. Up to 30 floors, each an 8 by 8 grid of 64 rooms. The mainframe sits somewhere on floors 27 through 30. Floors generate randomly, so no two runs match. The CRPG Addict compares the presentation to Wizard’s Castle, a text-mode grid ancestor.

Encounters resolve six ways, and only one is combat. Meeting a hostile employee offers: (d)eal or trade, (b)attle, (s)trategy, (t)rick, (e)vade, and (p)rank phone call. Outcome depends on the employee type and the operator’s statistics.

Foreknowledge is the difficulty knob. How much of the floor ahead is visible is set by the chosen difficulty, so the same map is harder when less of it is legible in advance.

The building fights back without fighting. A computer-controlled air vent can pull the operator up and deposit them on a different floor. The lights go out abruptly.

Resources. Weapons are office supplies (pencil, pen, paperclips, file folder). Currency is “chips and bytes.” Food has to be managed across the climb.

Class choice, mostly cosmetic. Commando, secret agent, detective, or private eye, with rolled statistics. The Addict’s playthrough found the rolled values looked much the same whichever class was picked.

Permadeath is enforced by deletion. Death removes the save file.

KN-86 resonance

The encounter menu is the strongest idea here, and it belongs to ICE Breaker. Six resolutions where one is a fight. Josh’s ICE Breaker premise is hacking a system against ICE, and a defender that can be dealt with, tricked, evaded, out-manoeuvred, or distracted is a richer opponent than one that can only be fought or fled. That maps onto a verb set rather than a combat stat.

The objective is a fact the operator carries out. “Return to the lobby with knowledge of the mainframe’s location” is an exfiltration win: the run produces something that has to survive the trip out. On the deck that is a dossier-commit shape, and it gives the intrusion loop a reason to end at a program rather than at a score.

Foreknowledge as the difficulty axis has a live implementation. The World Engine already tracks per-node revealed and online state, readable through world-node-revealed? and world-node-online?. Difficulty expressed as how much of the map is legible before entry needs no new machinery.

64 rooms on an 8 by 8 grid is a tractable region size. Small enough to render whole on the cell grid with room for chrome, and close to the node counts the live mission regions carry.

Hazards that relocate the operator are a defender move. The air vent moves the operator without consent, which is what ICE should be able to do: not damage, but displacement, so position stops being reliable.

Where this source does not fit

The roguelike half belongs to Tunnel Rat. Random floors, permadeath by save deletion, food management, and rolled classes are roguelike furniture, and Josh has ruled ICE Breaker out of that genre. Those parts read against the roguelike design guidance, where Tunnel Rat is the candidate concept and permadeath is already a chosen knob. ICE Breaker takes the encounter menu, the information objective, and the foreknowledge axis; Tunnel Rat takes the generation and attrition model.

The office-supply joke is a tone divergence. Pencils and paperclips as weapons is a comic register. The deck’s fiction plays intrusion straight, so the mundane-materials gag is a thing to notice and leave alone.

Sources and verification

Confidence: high on production facts (1987, DOS, Plemons and Shankman, shareware at $15, the 1987-08-29 date) and on the core loop and encounter verbs, which the CRPG Addict recorded from a completed playthrough and which the distribution listings corroborate.

Confidence: medium on two details. The mainframe’s floor range (27 through 30) and the floor count (up to 30) come from listing descriptions rather than from the game’s own text. The class list appears consistently across listings, and the observation that rolled statistics vary little by class is one player’s account.

The game is playable in a browser at the Internet Archive item above, so any detail a design decision rests on can be checked directly rather than taken from a description.