The game includes a simple compiled programming language, conceptually similar to AWK . Each entry includes a number of patterns or clauses, that if all are true, invokes one or more actions.

The logic for each room is stored in various buffers starting at E80F (for the Town Square). These are accessed by the routine at EABF. The routine starts by checking for patterns, but switches to checking for actions taken if those patterns are all true with byte F7. A new pattern is then identified with byte F6. Byte FF signals the end of the logic.

Each room also contains a set of custom code that can be executed on entry. These are stored in a table at EEF3. If there is no custom action for the room, the table's entry is F2F6, which is a simple RET instruction.

A pattern is identified by the byte sequence opcode,[operands]. The number of bytes used as operands is dependent on the specific opcode.

The routines to handle each pattern is stored in a lookup table at E7E9.

Value	Instruction	Description
0	AT_OBJ(n)	True if the player is standing next to the 'n'th object in the room.
1	HAS(n)	True if the player is holding object 'n'.
2	IS_SET(f)	True if the flag 'f' is set.
3	IS_OBJ(n,i)	True if the 'n'th object in the room is 'i'.
4	AT(x,y)	True if the player is standing at co-ordinates x,y.
5	AM(n)	True if the player is using the character with this ID.
6	NOT_HAS(n)	True if the player isn't holding object 'n'.
7	NOT_OBJ(n,i)	True if the 'n'th object in the room isn't 'i'.

The character IDs used in opcode 5 (AM(n)) are:

Value	Character
01	Wally
02	Wilma
04	Tom
08	Dick
10	Harry

An action is identified by the byte sequence opcode,[operands]. The number of bytes used as operands is dependent on the specific opcode.

The routines to handle each action is stored in a lookup table at E7F9.

Value	Instruction	Description
0	SWAP	Swap the least-recently picked up item for the nearest one in the room.
1	SWAPFOR( n )	Swap object with ID 'n' that the player holds for the nearest one in the room. Used when a combination of items held or near reacts to produce another one, such as swapping the sand for the cement when holding a full bucket.
2	SET( f )	Set flag 'f'.
3	RESET( f )	Reset flag 'f'.
4	SET(f, i)	Set the value 'x' to 'i'.
5	EARN(i)	Earn the amount of money indexed.
6	WALL	Build the wall. Only relevant in Wall Street.
7	SPACE	Enter the asteroids game. Only relevant when standing near a phone booth.
8	SAFE	Blow the safe, get the money and complete the game! Only used in the bank.
9	CHASE	Open up the floor and drop the player down to the "chase the shark" room. Most often used when some task needs to be completed at a location, but the player has the wrong character and items.
A	OUT	Enter the "out of town" room.

The money earned by various tasks is defined in a table at EC5C. Each entry in the table contains three bytes:

Byte	Character
0	Set to 1 if the task earning the money is completed, or 0 if not
1	Money low byte
2	Money high byte

Money is always given in multiples of £10.

The high byte is the hundreds part of the money. The low byte is the tens part of the money.

In both cases, only the top nybble is used (as a decimal digit can be represented as four bits).

Example : $00, $50, $01 = Entry 1, £150.

The maximum amount of money that can be earned is defined at ECFC as £4,000.

Morning, lunch and tea breaks and the end of the game are reached when a certain amount of money has been earned, defined in entries at ECF6. These are:

Byte	Character
£600	Morning tea break
£1,300	Lunch time
£2,100	Tea time
£4,000	End of game

The index of the next index into the buffer is stored in ECF5.

The computer characters run off a list defined at AEEA, which contains a target room for them to move to, where they will swap with the first item in the room. The list is terminated by FF.

Whenever a computer character has swapped with an item, it picks the next entry off the table to decide where it's going to move to. As different characters swap at different times, always taking the next room ID in the table, it looks pseudo-random to the end user.

The table at AD78 explains how the computer character needs to move between the current and the target room. Each entry contains a pair of bytes. The routine at ADBA, called when a character enters a new room, takes the cumulative difference between the two pairs of bytes (in the next room and the target room) and assigns it a "score". It compares it against a running "best score" (initialised to FF so the first entry will always return a better result), and picks the room with the lowest score, which moves the character towards the intended room.