1985 · U.S. Gold
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.
| 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 80 comments had 14 wrong, so between 11 and 27 % of the listing’s comments are likely wrong. How listings are checked |
| Build analysed | U.S. Gold disk, 1985 (C64 Preservation Project G64, time_tunnel[us_gold_1985](!), SHA-256 6bfb0bb1...2d2fc9); the program T1, $0900-$C5FD, is the same bytes on the collection's alternate dump |
| Copy | agent-draft |
| Tools | emulator: release v3.14.0, v3.14.0-linux-x86_64-gui.zip, disassembler: regenerator2000 0.9.20, host: Linux x86_64, Ubuntu 24.04.5 (cloud container) |
| Model | claude-opus-5-5 |
| Kit version | 0.0.277 |
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 | Of the listing |
|---|---|---|---|
| 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 570 comments. | |
| Sample 1 | claude-opus-5-5 | 14 of 80 comments wrong, so between 11 and 27 % of the listing is likely wrong. All 14 were then corrected. 60 of the 391 hand-written comments (12 wrong) and 20 of the 179 generated from the object tables (2 wrong, a template, corrected in all 89 it wrote) |
likely wrong the sample’s range corrected right, or likely right not yet measured
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:
zzap64-magazine-012, read 31 October 2026.| Feature | Status | Where |
|---|---|---|
| You are a gnome who wants to be King of the Gnomes; the document that says how is in seven pieces, one in each era | confirmed | the pieces are objects $04-$0A, one in each era but the mansion; all seven at the black hole show the message (hole_pass, $184E), and the staff it names ends the game in the throne room, era 9 (persia_cave, $1E9E; throne_room_entry, $1F99) |
| Play starts in the living room of Gnome Mansion, in the present | live | the start-up sets era 1, room 1 |
| A time machine in the mansion, missing a part that must be found in the house before it works | confirmed | the part is object $15; it appears on the living room's table when a bolt lights the log in the fireplace (living_room_pass, $11F3), and the machine runs once it sits at x $6F, y $4B (machine_button, $1311) |
| Seven eras besides the present: Stone Age 9600 BC, Magical Persia 893 BC, Mythological Greece 86 BC, Colonial Salem 1692, California Gold Rush 1849, Intergalactic Spaceship 3456, The Black Hole 9999 | confirmed | era names era1_name ... era8_name ($0BC2); the controls' screen shows the same seven years; the year chosen plus 2 is the era (machine_countdown_over, $10E4) |
| A time machine control room: select a new year with the joystick, RETURN goes back to the mansion | differs | each press of the button lights the next year and the stick pulled down leaves (controls_pass, $11C1); the room's own text says so: "FIRE BUTTON SELECTS NEW YEAR / DOWN JOYSTICK RETURNS TO MANSION" (controls_screen, $40AA); nothing reads RETURN |
| One puzzle in each era, solved by bringing the right objects, some carried from another era | confirmed | each era's per-pass routine tests where objects lie: the gold rush $138D, the black hole $1801, Persia $1927, the stone age $1FEE, Greece $22ED, the spaceship $27D8, Salem $2C7A |
| The gnome carries one object at a time | confirmed | one carried slot and object, $74 and $75; picking up needs empty hands (play_button, $361D) |
| Objects can be picked up, dropped, set in motion, and things such as doors and lifts moved when he stands near them | confirmed | pick up and drop (play_button), the mansion's doors (door_check, door_use), the gold rush's lift and the spaceship's levers in their eras' routines |
| A lightning bolt (the box says lasers) fired with the button when facing left or right | confirmed | object $11, fired by play_button when there is nothing to drop or pick up and the gnome faces left or right |
| A closet, entered by holding the button for a few seconds, from anywhere in time; it stores up to eight objects | differs | held for 128 passes (2.56 seconds) the button takes him to era 2, room 9 (play_state, $34B0), but he cannot leave while five or more objects lie there, and each piece of the scripture counts five (closet_pass, $116A): it holds four objects, and never a piece |
| Flick-screen rooms seen from a raised angle | live | |
| Joystick control | live | the main loop reads both control ports, $DC00 and $DC01, ANDed together |
| A pause key | live | F7 toggles $AF (keys_read, $38FF); while paused only the clocks $23 and $BD count |
| One game lasts until it is solved; there are no lives (Zzap!64) | confirmed | hazards (the scorpion, the stalactites, the bats, the snake, Medusa's shot, the cave's pit, the moon's air) send the gnome home, or back into the ship (gnome_hurt, $3378; persia_cave, $1E9E); no variable counts lives |
| Credits screen: "U.S. GOLD, LTD. PRESENTS TIME TUNNEL BY APPLIED SYSTEMS ENGINEERING, INC. (WITH HELP FROM ON-TIME SOFTWARE) SAN JOSE, CA COPYRIGHT 1985" | live | text at $0FA9 |
Found in the code, not in the manual.
hole_message_screen).persia_lid, $1CA1), set on the basket, writes its new x and y to the stored position of object 4 + its sprite slot (one of objects 5-$0B, most of them pieces of the scripture) rather than to its own.$C5A8, a cartridge header (CBM80) at $0900, and the words "Bytes/sector:" in the throne room's character set.$A are the same code. Voice 3 is set up for noise, but nothing reads its output ($D41B).$46 and $47, Medusa's fourth frames, the dynamite's fifth frame and the basket lid's third row.$1EEE (one of the ten jumps to go_home) and $1BE5; two tests of $B6 at $2D97 whose branches both lead on.salem_broom_park, $2CA5). Read from the code and not tried.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.