Doctor Who and the Mines of Terror

The quest

Stop the machine, take what matters, get out alive

The game has one goal it insists on: leave the mine alive, in the TARDIS or in an escape pod (game_event_handler, $9102). Everything else is optional. Each optional goal doubles the escape bonus, which decides how well the Time Lords think the Doctor did (scoring), and each links to how it is done on the Solution tab:

Rock, clamped ladders, bad air, a security gate, and a code lock stand in the way, and the tools that clear them lie around the mine.

The Maps tab shows where each of them is, and the Solution tab takes the steps in order.

Pockets and items

Everything the Doctor can pick up

Twenty-four objects lie in the mine when a game starts, and the Doctor can carry any of them, Splinx too. Each pin in the Map column opens the Maps tab on that object, one pin for each copy.

Each object drawn from its starting frame ($1D30) in its own colour ($1850), with its name from the game's own table: ten characters at $1770 plus the offset in $1720, in the game's private alphabet.

The Doctor carries one item in his hands and up to four more in his pockets, and the status bar shows all five. F5 picks up any object within reach, from $30 to $4F, or Splinx (pickup_nearby, $A929). Using an object that works only in certain places compares his position with that object's table of points (use_item_update, $BACC). The keys that move things between hands and pockets are on the Controls tab.

Splinx

A robot cat with a ten-step program

Splinx can follow the Doctor, stay put, or run a program of up to ten commands, written in a language the story calls CYBAL.¹⁶ Press S to open its programming screen.

Splinx fetches items the Doctor cannot reach or carry. To send it somewhere, the Doctor drops one of his four markers there with F3. The markers are objects $30-$33, kept in the marker box of the status bar.

On the programming screen the joystick moves between the commands and along the ten steps of the program, and fire writes the command into the step. The three choices on the right set Splinx's mode: shut down, follow the Doctor, or execute the program (splinx_update, $B1A0).

The battery starts full at 24 units. It loses one every 1,024 frames, about 20 seconds, while Splinx follows the Doctor or runs a program, so a full charge lasts about eight minutes of work. Shut down, Splinx uses nothing. The gauge on the programming screen is a sprite the game redraws from the battery level ($B07D).

The lift and the car

A lift with eight stops, and a car that runs sideways

Ladders are not the only way around the mine. A lift carries the Doctor up and down, and a car carries him sideways along two stretches of track.

The lift (lift_update, $A13C) travels between eight stops, from the top one to the bottom one and back, waiting at every stop before it moves on ($A12C). It takes a passenger only at the end of a wait: just before it sets off, it checks whether the Doctor is standing on its floor within 18 pixels of its middle (lift_check_board, $A252). A player who steps on as the lift leaves is left behind. Close to the lift, the pocket keys do nothing ($A1F1), so the Doctor cannot drop or use anything beside it.

The car ($A2B9) works the same way sideways. It shuttles from one end of its track to the other, waits longer than the lift at each end, and checks for the Doctor just before it leaves ($A2B0).

The prisoner

One controller takes the Doctor prisoner instead of killing him

Every other controller kills the Doctor at a touch. The one that patrols high on the right of the mine marches him through a doorway the first time it catches him, and walls him in.

Controller $22 starts at x $0C40, y $0588, just right of the doorway. When it reaches the Doctor while he stands on a floor (his height is 8 more than a multiple of 16), it does not shock him. It sets a flag instead (controller_touch, $CE28), and while the flag is set the game takes the joystick away: the Doctor cannot fire or use his pockets, and he walks by himself to a point just inside the doorway ($C9AB). Once he is within 16 pixels of that point, the controller walls up the doorway behind him, redrawing its block with a column of rock (block $04 becomes $F1, controller_wait, $CF44), and goes back to its patrol.

That wall is the one a blast opens ($C22E). A DETONATOR or the EXPLOSIVES going off within 32 pixels of the doorway clears it, and the same blast destroys any controller in reach (blast_damage, $C1CB). Until the wall is blown, no controller comes after the Doctor ($CE8A). He is taken prisoner only once: the flag survives a regeneration ($937F), and every later touch from a controller is fatal.

Dangers

Five regenerations, and the ways to lose them

When the Doctor dies, he fades away pixel by pixel, the cause scrolls across the status bar, and he comes back at the last restart point he passed. Choose a cause to decode its message from the game's tables.

The Doctor starts with five lives. They are drawn as five stars in the status bar's item field, which is why the stars disappear when he picks something up ($94AC). After the last one, the game is over.

The fade is the TARDIS's own effect turned on the Doctor (doctor_draw, $CB6B). For the last 127 frames of the death, every fourth frame, the game copies his two frames afresh and clears more of their pixel pairs, six more each time, in the shuffled order the TARDIS landing uses (dissolve_sprite, $FEA9). The Graphics tab plays it.

Creatures

Who else is in the mine

The Doctor shares the mine with Splinx, the Rijans who work it, the Master's controllers, a madrag and her eggs, and the Master himself. Each is drawn here from its own frames, as the game animates it.

Escape

How the Time Lords mark you

The game ends when the Doctor leaves in the TARDIS or in an escape pod. What he brings with him doubles his bonus, and his score decides what the Time Lords think of him.

Doing everything gives a bonus of 1,024 doubled five times, 32,768 (game_event_handler, $9102). The time counter adds up to 10,800 more, and in practice it nearly always adds all of it, because of a slip in the frame counter. The end screen says whether the Doctor HALTED THE PRODUCTION OF HEATONITE, from the same test as the last doubling (messages at $95CB).