Doctor Who and the Mines of Terror

Controls

A joystick for moving, the keyboard for everything else

The joystick in port 2 moves the Doctor and makes him jump. The keyboard can move him too, and it holds every other command: the pockets, Splinx, giving up a regeneration, and saving.

Input	What it does	Where
Stick left and right, or Z and X	walk	`$8F47`
Stick up and down, or ; and /	climb a ladder	`$8F64`
Fire, or RETURN	jump	`jump_arc_step` `$A0D4`
F1	moves the selector across the marker box and the four pockets	`$A530`
F3	puts the item in the Doctor's hands into the first empty pocket; drops a marker; with empty hands, takes out the selected item	`$A575`, `pocket_take` `$A60C`
F5	standing still, picks up the object in front of him; holding an item, uses it	`pickup_nearby` `$A929`, `use_item_update` `$BACC`
F7 and a direction	throws the item in his hands; two can be in flight at once	`throw_start` `$A7D7`
S	the Splinx Programmer	`$AF58`
R	forced regeneration: give up a life and start again	`$9051`
D, CTRL+D, L	the save menu, in one place only (Discoveries)	`$8FA4`

The input routine (read_input, $8F24) runs once every pass of the game's main loop. It reads the joystick and six rows of the keyboard, and turns them into flags that the rest of the game reads: one for left or right, one for up or down, one for jump, and one each for the keys.

What each object does when the Doctor uses it is on the Gameplay tab, and his walking and climbing frames are on the Graphics tab.

Jumping and falling

A fixed arc, and a fatal drop of 96 pixels

A jump always has the same shape, and the direction is fixed at take-off. Move the landing point to see where a jump turns into a fatal fall, and the Doctor fade away when it does.

Land below take-off

Each frame of a jump moves the Doctor one pixel across: for 24 frames he also rises a pixel, for the next 16 he stays level, and then he falls a pixel a frame until something stops him (jump_arc_step, $A0D4). The direction comes from the stick at take-off and cannot change in the air.

The game measures a fall from where the Doctor starts moving down to where he stops (fall_track, $CD3A). A drop of 96 pixels or more kills him, with the message A FALL (fall_check, $CD62). The rise of a jump is measured separately and never counts, so the fall of a jump starts at its highest point: landing 72 pixels or more below take-off is fatal.