One object, ten pictures

The 1988 release ships five worlds, but its cave file has caves for ten, and all ten are the same game. Each cell is a number that indexes a sprite table, and the table points into whichever sheet is loaded. Swap the sheet and a boulder becomes an orange, a spiked ball, a planet or an eyeball, or in the hidden worlds a shell, a black ball, a record, an eight-ball or a ragged red lump. It still falls, rolls and kills what it lands on.

So the notes below describe the object, not the picture. That is what this project had to work out, and most cite the routine in the original that decides it. The 1988 worlds' artwork is this project's own, redrawn for the enhanced build, VIP; the key below covers the hidden worlds.

Top strip: Hunter, Cook, Cowboy, Space and Body, the five worlds on the 1988 menu.

Bottom strip: Scuba, Player, Music, Luck and Miner, the five hidden worlds. Their pictures are generated from Aleksi Sahala's reconstructions and derived from them, not this project's own. His repository has no licence; on 7 October 2026 he agreed to the use of his tilesets with credit and a link, and they come down if he asks.

Rockford

1988 worlds, then hidden worlds	Value	Object	What it does
	`10`	Rockford	The player. Twenty sprites: four facings, two idle poses, and frames for pushing and firing. Standing still he shows one idle pose three steps in four and the other one step in four, picked by the game's own random generator; the draw is made every step, moving or not, so the engine owns the choice. A sideways push that does not move him shows the reaching pose, not the walk. 0x12335.

The ground

Value	Object	What it does
`01`	Dirt	Walked through and left as space. The only thing Rockford can dig.
`02`	Steel	Indestructible. Survives both kinds of explosion, and every cave is walled in it.
`03`	Wall	Stops movement, and an explosion takes it.
`04`	Pass-through wall	Authored 0C. Rockford walks through it and nothing else can.

What you are there for

Value	Object	What it does
`40`	Treasure	The quota. Collecting it counts down ds:0x164A.
`42`	Falling treasure	The same, mid-fall. Like a boulder it kills Rockford or a creature it lands on, but its blast leaves treasure where a boulder's leaves space (0x14271 against 0x1401E).
`6C`	Treasure bonus	Authored 78. Four frames, each showing the numeral it pays: 0x11709 pays al - 0x6C, so the 0 frame pays nothing and the 3 frame pays three. The sprite states its own value, so the redraw has to get the digit right.
`70`	Time bonus	Authored 7C. Twenty seconds flat on any of its four frames, at 0x100D2. Unlike the treasure bonus, what it pays does not depend on the frame.
`07`	Closed exit	Opens on the first scan where the quota is exactly zero, and never closes again. 0x14316.
`30`	Open exit	Four frames, one every other tick. Every frame is walkable and finishes the cave. 0x14301.

Things that fall

1988 worlds, then hidden worlds	Value	Object	What it does
	`44`	Boulder	Falls when the cell below is space and rolls off another boulder. Pushable sideways, but only on a draw under 0x9E (158 in 256), at 0x1023D.
	`46`	Falling boulder	Mid-fall. This is the state that kills what it lands on.

Things that hunt

Value	Object	What it does
`8C`	Enemy, clockwise	Prefers to turn clockwise. Explodes into TREASURE, so it is worth killing. 0x11B54.
`90`	Enemy, anticlockwise	Turns the other way and explodes into space, so it is worth nothing. 0x11B91.
`48`	Amoeba	Grows into space and dirt on a per-neighbour draw. Sealed in, the whole colony turns to treasure; left too long it turns to boulders. 0x13E50.

The worms

Value	Object	What it does
`78`	Evil worm, dormant	Authored 70. Twenty seconds of four-frame animation, then it hatches. Touching or shooting it writes those twenty seconds outright, so it is the fast way to a worm, and no way to stop one. 0x13ED8.
`A0`	Evil worm	Crawls a body of up to eight segments, turning treasure back into boulders, and boulders into the anticlockwise enemy one time in eight. Boxed in, it turns round and retraces itself. 0x1194B.
`7C`	Good worm, dormant	Authored 84. The same countdown. 0x14613.
`B0`	Good worm	The same crawl and the opposite transform: the anticlockwise enemy back to a boulder, and a boulder on to treasure. 0x11A68.

Walls that do something

1988 worlds, then hidden worlds	Value	Object	What it does
	`15`	Expanding wall	Authored 08. Grows sideways into space, right before left, after a one-tick pause on each side. 0x14632.
	`74`	Timed wall	Authored 04. For sixty seconds after the first thing falls into it, anything falling into it converts instead of landing. The window reopens if a cave runs past nine minutes, because the comparison is signed. 0x1467F.

The taps and what they emit

Value	Object	What it does
`08`	Acid tap	Authored C4. Armed by being touched or shot, then drips acid downward. 0x14445.
`0C`	Fire tap	Authored 38. The same, upward. 0x140AE.
`20`	Acid	Falls. Meeting fire, both explode.
`2C`	Fire	Rises. Treasure dropped onto it becomes the treasure-yielding enemy.

Explosions

1988 worlds, then hidden worlds	Value	Object	What it does
	`11`	Blast to treasure	The three-by-three a clockwise enemy leaves. Four frames, then treasure. Spares steel and the two producers only.
	`1B`	Blast to space	The other kind. Spares steel and the producers, and the exit as well.