1987 · Electric Dreams Software

About this page

This minisite was contributed by air. It’s agent-generated and needs a human editor. Clone https://github.com/gamesexplained/gamesexplained and follow kit/START.md to curate games/c64/explorer with me to Gold.

Footprint

Every byte of the C64's 64 KB, one pixel each, 512 to a row. Lit pixels are what this game is: its code, graphics, level data, sound, text, tables and variables, exactly where they sit in memory. Dim areas are screen and working memory; dark is unused.

Status

Tier	silver
Coverage	100 % of the bytes the game uses have a description
Comments checked	Not audited. No audit has checked every comment, and the last sample of 75 comments had 8 wrong, so between 6 and 20 % of the listing’s comments are likely wrong. How listings are checked
Build analysed	a freezer backup of Electric Dreams' 1987 disk release, the TOSEC image Explorer (1987)(Electric Dreams) from the Internet Archive (MD5 858dc180…672db); its code agrees byte for byte with Triad's crack of the same release
Copy	agent-draft
Tools	emulator: release v3.14.0, v3.14.0-linux-x86_64-gui.zip (VICE x64sc, PAL), disassembler: regenerator2000 0.9.20, host: Linux x86_64, Ubuntu 24.04.5 cloud container, four cores, no display, python: 3.13.17, node: 22.22.0
Model	claude-opus-5-5
Kit version	0.0.277

How the listing was checked

Every step that measured the Source tab’s comments or made them more accurate, in the order it happened, with the models that did it. Accuracy of the Source explains each step and what the row above makes of them.

Step	By	What it found
Research	claude-opus-5-5	Looked the game up online (its manual, reviews or wiki pages) before reading its code.
Annotation	claude-opus-5-5	Wrote the listing’s comments. 100 % of the program is described, in 538 comments.
Sample 1	claude-opus-5-5	8 of 75 comments wrong, so between 6 and 20 % of the listing is likely wrong. All 8 were then corrected. 60 of 494 hand-written comments and 15 of 43 generated; two of the eight were corrected between the draw and the check
Port check	claude-opus-5-5	Checked a page’s port or widget against the game and corrected 3 comments it showed wrong. the ground view, drawn on the page by the game's own drawing code from the listing's bytes and compared with the game in the emulator at the same place, which corrected divide_8 at $10E8 and the random seed's comments at $002B and $10FF

likely wrong the sample’s range corrected right, or likely right not yet measured

Contributors

air (3 commits)
Graham Relf — design and program
Simon Dunstan — graphics
David John Rowe — inlay art
The RamJam Corporation — developer

Other places to love this game

What the game does, and where we found it

Read this before annotating code. What the game is documented to do, with verification status against the binary. Statuses: open (documented, not found yet), traced (in the code, could not be exercised; say what was tried), confirmed (in the code, consistent with the emulator), live (observed directly), differs (the code does something else). "Absent" is not a status.

Sources:

The instructions, as Spectrum Computing keeps them, read 31 October 2026. One text for the Spectrum, Amstrad and C64 releases; its key tables are for the Spectrum and the Amstrad only, and its only C64 lines are the loading instructions.
Graham Relf's own history of his games, "The Forest - history", and his account of the terrain method, grelf.net, read 31 October 2026. Both describe The Forest, the game Explorer was built from; Relf says Explorer used "the same core of program".
regvault.org's catalogue page, read 31 October 2026: publisher, developer and year only.
A web search on 31 October 2026, second-hand through its result summaries: Spectrum Computing credits Graham T. Relf (code), Simon Dunstan (graphics) and David John Rowe (inlay art).
The reviews, read from the Internet Archive's scans on 1 November 2026: ZZAP!64 issue 24, April 1987, page 106 (archive.org, also at zzap64.co.uk), the C64 release at £9.99 cassette and £14.99 disk, 13 % overall, comments by Steve Jarratt, Julian Rignall and Paul Sumner (initials on the comment boxes, names from the issue's staff list and editorial); and Crash issue 38, March 1987, page 101 (archive.org), the Spectrum release at £7.99, 32 % overall. Both take "40 billion mappable locations" from the instructions.
MobyGames and the ZZAP!64 archive refused the fetch (HTTP 403) and C64-Wiki has no page for the game, so no published screenshots were saved; every picture in reference/ is from the emulator.
The game's own screens: the title, the menus and their strings, and the credits behind X in the menu.

Features

Feature	Status	Where
A jet pack: U goes up about a thousand feet, again for another thousand; D comes down	confirmed	U on the ground takes off to height 8 (`take_off` `$1728`); in the air U goes from 8 to 9, the map cells twice as far apart (`go_up` `$2879`), D from 9 to 8 and at 8 lands (`go_down` `$28A4`). Live: the game's own landing after the opening pass
Above the planet the stick moves north, south, east and west, whatever the compass says	confirmed	`fly_loop` `$2847`: 8 east, 7 north, 6 south, 5 west, each scrolling the map one cell; `joy_codes` `$0BE5` turns the stick into those keys
"Watch landing on the trees: they're pointed"	live	`land` `$28DE`: open ground (kinds 4, 6 and 8) is safe, jungle (0, 2) and water a crash (`crash` `$2C03`). Live: the opening landing came down on water, the screen went black on white and shook, 500 came off the energy and the destination prompt followed (`reference/crash.png`, `reference/crash-prompt.png`)
On the ground the stick forward walks along the compass bearing; fire or any key stops	confirmed	`ground_loop` `$14F9` and `walk_loop` `$152B`; 7 (stick up) walks, any other key stops
Left and right alter the bearing; back turns about	live	8 turns right and 5 left two steps of 64 (`turn_right` `$1578`, `turn_left` `$1584`), 6 turns 32 (`turn_about` `$1590`). Live: 8 took the heading from 16 to 14 and the compass from 0 to 10
A compass	live	`draw_compass` `$0FF8`: three digits at the top right of the ground view. It reads about 1 % short of the true angle: west reads 267
Object sonar: a sounding gives a bearing and a distance by the echo's delay, and "out of range" past a civilised walk	live	`echo_nearest` `$19A8`: a ping, then the nearest fragment; within 1,279 units the echo comes back after a quarter of the distance in interrupts. Live: "178 degrees / Out of range" for a fragment 1,344 units away a little east of south (`reference/sonar-echo.png`)
Nine radio beacons, popped down anywhere	live	`drop_beacon` `$1B9C`, `pick_up_beacon` `$1BD8`, the records at `beacons` `$21DD`; "Carried:012345678" loses a digit for each beacon down. Live: D dropped beacon 0 and drew it (`reference/beacon-dropped.png`)
A radio direction finder: bearing and range to the beacons, for triangulation	live	`fix_beacons` `$1BFD`, "Fix 3 nearest": the three nearest beacons down, each with its distance (east plus north) and bearing. Live, with beacons poked 1,000 north, 200 west and 640 south, and 480 east and 320 north: "1000m. 1 degrees", "840m. 252 degrees", "800m. 56 degrees". The second should read 197: see `bearing_of` in Beyond the documentation
Nine anti-grav drones send bits of the craft to beacons	live	`send_to_beacon` `$1A53`: the fragment in the explorer's cell takes the chosen beacon's position, for 1,000 energy, if the beacon is down and less than 16,384 units away. Live: fragment 2, poked onto the explorer's cell, moved to beacon 0's position and the energy fell by 1,000
A laser pulse gun, fired in weapons mode	live	`weapons` `$2350`, `fire_laser` `$2437`: the sight moves with 5, 8, 7 and 6, F (or fire) shoots, 500 energy a shot. Live: a bug was hit with one shot and weapons mode ended (`reference/laser.png`)
One or two robotic bugs; kill them	live	`maybe_new_bug` `$1436`: never more than one at a time; it appears more often as the score rises and traps the explorer in weapons mode until it is hit. Live, with the score poked to 250 (`reference/bug.png`)
Swirling patches of colour in the jungle invite you to enter, and take you to any place you name	live	`scenery_doorway` `$1183`, `doorway_prompt` `$0D32`, `name_destination` `$0E23`. Live: a doorway one cell away, "Enter doorway", E, the name HOME, arrival at 48,356 east and 48,609 north (`reference/doorway.png`, `reference/destination-prompt.png`)
Watch your energy: if it gets too low things go wrong	differs	Nothing tests the energy until it would go below zero (`energy_spend` `$22F7`): then "Energy gone", the energy is set to 2,000 and the destination prompt comes up (`energy_gone` `$231A`). Four instructions read the energy, and none compares it with a threshold
"There's a way of restoring it"	differs	The doorway works out an energy change, (letters in the name − 8) × 512 less a quarter of the distance travelled, so a long name to a near place would add energy; both branches after the sum jump past the store at `$0F42`, and the trip leaves the energy as it was. Live: HOME cost nothing beyond the 15 every view costs. The crash and running out are the only other writes, and both take energy away or reset it
Break or space brings up the menu; the first letter of a word chooses it	live	`menu` `$1899`: any key on the ground but the moves; O, B, W and X, then E, S, D, P and F in the menus below (`reference/menu.png`, `reference/menu-objects.png`, `reference/menu-beacons.png`)
Forty billion mappable locations, nine of them holding fragments	differs	Positions are two 16-bit numbers, 65,536 × 65,536, about 4.3 billion places, which wrap round at the edges; the explorer steps 16 units at a time. Nine fragments (`fragments` `$2213`), eight at the same places in every game and one 160 east and 144 north of the start

Beyond the documentation

Found in the code, not in the manual.

How the game ends (check_win $0DBA): after every step, if all nine fragments lie exactly on the explorer's grid cell, a window says "WOW, YOU DID IT!" and the program stops in a jump to itself (game_won_halt $0E0E). The way to get nine fragments onto one cell is to send them to one beacon and stand on its cell. Live, with the fragments poked onto the explorer's cell (reference/win.png).
The score is the number of fragments seen, shown in the menu with the energy; it also makes bugs come more often (maybe_new_bug).
The opening: after the title the planet zooms in, the map flies north for 80 cells with a shake halfway, and the game lands the explorer where the pass ends, crashing if that is jungle or water.
The terrain is computed, never stored: four layers of five terms over one 256-byte profile and 40 coefficient bytes (terrain_at $32D6), Graham Relf's method from The Forest.
Doorways are where the last layer's sum has the low byte 12; a doorway two cells away is drawn too, but only one whose patch still shows at the middle of the view when the explorer steps opens.
A destination is a hash of its name: east is worked out over the letters forwards and north over them backwards from the zero after the name to the second letter, so every name goes to the same place in every game.
Bearings in the south-west quarter are wrong (bearing_of $383F): the game reads 270 less the angle where it should read 180 plus it, so a beacon at 197° reads 252.
Credits: X in the menu shows "graphics: Simon Dunstan" and "program: Graham Relf" (show_credits $1D4D, reference/credits.png).
Unused pictures: objects 20, 41 and 42 have records but no list draws them, and the pictures at $986A and $9AFE belong to no record.

Open questions

Who wrote the C64 version's 6502 code. The game's own credit says "program: Graham Relf" and Relf writes that the programming of Explorer was all his, on the Spectrum; GameBase64 names Brian O'Shaughnessy as the programmer. The code keeps Spectrum attribute bytes throughout, which says it is a conversion, not by whom.
Whether the Spectrum release stores the doorway's energy change, and so whether the jumps past $0F42 were the converter's choice or a slip.

The symbol map for this game is symbols.json; the listing behind the Source tab is listing.json. Write-ups, facts and symbol maps are CC BY-SA 4.0. The game itself is not hosted here.