BBC Micro B

Copy and paste the program text in the file below to Owlet

Surviving the Darkness: A Guide to “Goblin Cave Adventure”

Picture this: It’s the early 1980s. The room is dark, save for the warm, phosphor glow of a CRT monitor. The mechanical clatter of your Acorn BBC Micro keyboard echoes as you frantically type “KILL NASTY GOBLIN”. You are playing Melbourne House’s legendary 1982 text adventure, The Hobbit.

What made that game so magical wasn’t just the graphics or the prose; it was the fact that the world felt alive. Characters didn’t just wait for you in rooms—they wandered, they fought, they got lost, and they died while you were off doing something else entirely.

I wanted to recapture that exact feeling. I wanted to build a game that felt like a lost cassette tape from 1984, but with a modern twist: infinite replayability.

The result is Goblin Cave Adventure, a procedurally generated, living text adventure written entirely in authentic BBC BASIC II.

The Motivation: 32KB of Living Ecosystem

My goal was simple but technically daunting: Could I build a procedurally generated maze, an auto-mapper, a real-time command parser, and an ecosystem of autonomous NPCs that loot items, unlock doors, and fight each other… all within the brutal constraints of the BBC Micro’s memory?

Because BBC BASIC II lacks modern luxuries like multi-line IF…ENDIF blocks, the code is a beautiful, tangled web of single-line logic, clever array management, and Mode 7 Teletext trickery.

But the effort was worth it. The cave system is a living MUD-lite. If a wandering Goblin hits a locked door, he’ll turn around—unless he happened to find the matching key on the floor a few turns ago, in which case he’ll unlock it! If Gandalf crosses paths with the Great Goblin, they will fight to the death. If you are a room away when this happens, you might just read: “You hear a lock click,” or “A scraping noise echoes down the passage.”

It is a game where you are not the center of the universe. You are just trying to survive it.

How to Play: Surviving the Depths

Your overarching objective is to clear the caves of darkness. There are 5 hostile enemies (Gollum, the Vicious Warg, two nasty Goblins, and the Great Goblin). If you can eliminate them all, you win.

The Interface & Stats
At the top of the screen, you will see a fixed, non-scrolling yellow HUD tracking your vitals:

• HP (Hit Points): You start with 20. Take a hit, lose 1 HP. Hit 0, and you die in the dark.
• STR (Strength): You start at 4. (Hint: if you find and TAKE STING, your strength jumps to 6!)
• ENEMIES: The number of bad guys left alive. Friendly dwarves and Gandalf don’t count—and if they kill a goblin for you, this number will tick down!

The Commands
The parser is forgiving (case-insensitive) but strictly 1980s. Here is your survival toolkit:

• Movement: N, S, E, W, U (Up), D (Down).
• Look Around: L or LOOK.
• The Auto-Mapper: Type M or MAP. This is a massive quality-of-life feature! It pauses the game and draws a complete Teletext map of everything you have explored on both the Upper and Lower levels.
• Inventory: I, INV, or INVENTORY.
• Item Management: TAKE [ITEM] and DROP [ITEM]. (e.g., TAKE STING, DROP KEY).
• The Ring: WEAR RING grants you 10 turns of invisibility. Enemies will not ambush you, and if you attack them, they will thrash blindly in the dark! Type REMOVE RING to take it off.
• Doors: Four colored doors (Golden, Curious, Iron, Red) block your path. Use OPEN, CLOSE, LOCK, and UNLOCK to interact with them (assuming you have the right key!).
• Combat: Type FIGHT, ATTACK, or KILL (e.g., FIGHT GOBLIN).
• Spying: Type NPC at any time to pull up a debug screen showing which NPCs are alive, dead, and exactly what items they have looted from the map!

The Real-Time Twist
While it is a turn-based text adventure, it is also watching the clock. If you sit at the > prompt for 30 seconds without pressing a key, the game will automatically execute a WAIT command. The world will tick forward, enemies will move, and you might suddenly find yourself ambushed by a Warg while you were sipping your tea!

Ready to Descend?

If you want to step back into 1984, fire up a BBC Micro emulator (like BeebEm, B-Em, or JSBeeb in your browser), paste in the code, and type RUN.

Keep your wits sharp, let the dwarves do the heavy lifting if you can, and whatever you do… listen closely to the noises in the dark.

Google AI Studio has helped me create an exact map of my Exploring Wilderland game.

This includes the starting positions of the NPCs as well as the objects. I say “starting” since NPCs can pick up objects and randomly drop them again. Not all the NPCs move in the game.

https://retrorendezvous.org/wp-content/uploads/2026/01/TheHobbitMapEnglish-scaled.png

Here’s the equivalent map in Spanish:-

https://retrorendezvous.org/wp-content/uploads/2026/01/TheHobbitMapSpanish-scaled.png

This is the final version of “Exploring Wilderland” – a BBC BASIC game based on the original “The Hobbit” text adventure game by Melbourne House

This is running in Owlet, so you’ll need to click into the righthand window in order to start typing commands for the game.

Click HERE to run in Outlet

After some battling with logic bugs and memory management, I’m happy to share the working version of Exploring Wilderland.

This is a text adventure running in Mode 7 on a standard BBC Model B. While it looks like a standard adventure on the surface, underneath it’s running a simulation where NPCs (Thorin, Gandalf, Goblins, etc.) are actively competing with you.

Here is the rundown on how to play and a look under the hood for those interested in the code.

How to Play

The Objective:

The game has 10 valuable treasures scattered across 52 locations (from Beorn’s House to the Lonely Mountain). To win, you must find and TAKE all 10 items. Once your inventory holds every treasure, the game detects this and you win.

The Catch:

You aren’t alone. There are a number of NPCs (12 altogether) with some of them wandering the map. They will move between locations, open and close doors, and—most importantly—pick up and drop items. If you can’t find the Valuable Treasure, chances are a goblin (or even Thorin) has picked it up and walked off with it! You might have to follow them and wait for them to drop it.

Commands

The parser is designed for speed. You can abbreviate almost all commands.

The parser is quite basic, so if you use backspace or delete, it won’t recognise a command. Try and get commands typed in right first time!

Navigation: N, S, E, W, U (Up), D (Down), NE, SE, etc.

Interaction:

OPEN (or O): Opens a door if one is present.
CLOSE (or C): Closes a door.
TAKE (or T): Note: This command takes ALL loose objects in the current room. You do not need to type the noun (e.g., just type T, not TAKE SWORD).
DROP (or DR): Drops ALL items you are currently carrying.

Info: LOOK (L), INVENT (INV), SCORE (SC), HELP (H).

Strategy: WAIT (or WA). This passes time without moving, allowing you to see NPCs enter/leave or interact with the room. JUMP (or J) allows you to jump to a random location in the game.

Further Help

The map pretty much follows the original Hobbit text adventure, but the more random parts of the map (stuck in Goblins caves) have been toned down.

You can see the original “Guide to Playing the Hobbit” by Melbourne House to get a sense of all the locations. The location numbers in my game (in the DATA statements) match the location numbers in the book, so if you get lost, then the guide will be invaluable.

Click here for Guide to Playing the Hobbit PDF

Code Insight Under the Hood

For those looking at the listing, here is how we managed the memory on the Model B:

1. Data Type Optimization

We were hitting memory limits, but rather than making the code unreadable by renaming every variable to A$ or X%, we optimized the data structures.
Originally, door statuses (“Open”/”Closed”) were stored as strings. We converted this to an Integer array (doorStatus%), which saves bytes for every door and is faster to process. We also stripped REM statements to claw back space.

2. The “Living” AI (PROC_NPC)

The heart of the simulation is in PROC_NPC. Every turn, each NPC rolls a die:
They have a chance to OPEN or CLOSE a door if they are near one.
They have a chance to TAKE items if present, or DROP items if they are carrying them.
They attempt to move to adjacent rooms using the same exit data the player uses.

3. Two-Way Door Logic

A tricky bug we solved involved doors. In many adventures, opening a door only updates the room you are standing in. In this game, PROC_OpenDoor and PROC_CloseDoor instantly calculate the location on the other side of the connection and update the exits for both rooms simultaneously. This means if Gandalf opens a door from the inside, you can walk in from the outside immediately.

Tweaking the Game

If you paste the code into your emulator and want to mess around, here are the key lines to look at:

Line 280 – Sets the starting location (normally set to 6) – so you can get the game to start in locations 1-52

Change the AI Personality (Line 924)

Currently, the code is: 924 action=RND(4)
This gives NPCs a 25% chance to try Opening, Closing, Taking, or Dropping.
Change it to RND(10) to make them less hyperactive (they will mostly just walk around).
Change it to RND(2) if you want a chaotic game where doors are constantly slamming shut!

Change the Win Condition (Line 670)

Currently, you need all 10 items (LEN(Inventory$)/2=NoOfObj%). You can lower this number if you want a quicker game.

I hope you enjoy exploring Wilderland!

My next BASIC coding project is to squeeze a very simplified version of the classic text adventure game “The Hobbit” by Veronika Megler, Philip Mitchell and David Johnston into a BBC Basic program. This would be for a 32K BBC Model B. I’ll be using the Owlet editor in the main and cross checking the code on my own BBC Micro.

See this Stardot forum post for progress on this project

Like many of you, I enjoyed this landmark game and it stuck in memory. I coded some of my own text adventures at the time and was fascinated with the process….certainly nudging me towards a database programming career later on in life. Let me know some of your own memories, experiences with this game – I’d like to hear them.

This project is mostly for nostalgia, but also taking on the challenge of squeezing a very simplified form of this landmark game into a BBC Basic version. Like many retro coding projects you think …. “Why not?”

My objectives are:-

1. To represent every location in the game in BBC basic, using tokens for the common words to save space.
2. To navigate between all the locations using the original mappings (though I may exclude the random-like maddening mazes such as the Dark Stuffy Passage)
3. To emulate the split screen user interface that the Hobbit had, with input text in the bottom quarter of the screen and output text in the top.
4. To keep everything in one program, not reading other files.

If there’s any memory left (I’ll use MODE 7) then we’ll see what else could be added. It would be fantastic to include NPCs wandering around the game map randomly, such as Thorin and/or Gandalf, so you could meet them as you wander.

My objectives are not:-

1. To have a clever parser. It’s just to input directions, to allow an easy exploration of the Wilderland.

Resources

The book “The Guide to Playing the Hobbit” by David Elkan (which I used to own) which gives a great breakdown of the game (from the internet archive)
https://archive.org/download/guide-to-p … Hobbit.pdf

Veronikia Megler’s website (one of the original authors of the game) includes some really useful information:-
http://veronikamegler.com/WL/wl.htm

– A map
– Room Database dump of the locations
– Even a rudimentary Spectrum emulator, displaying the state of the elements in the game

Using ChatGPT (ver 4)

For this project I’ve been using ChatGPT to start to compile the word tokens and the locations converted into text with token indexes inserted. It’s done quite well with this. I asked ChatGPT to look at this list of locations and pull out all common words that are greater than two characters:-

Beorn’s house
The Bewitched gloomy place
A big cavern with torches along the walls
A bleak barren land that was once green
The cellar where the king keeps his barrels of wine.
A comfortable tunnel-like hall.
A dark dungeon in the elven king’s halls.
The dark stuffy passage
The dark winding passage
The east bank of a black river
The elven king’s great halls
An elvish clearing with levelled ground and logs
The empty place
The forest
A forest of tangled smothering trees
The forest road
The forest road
Forest river
The front gate of the Lonely Mountain
The gate to Mirkwood
A gloomy empty land with dreary hills ahead
The goblins’ dungeon
The great river
The green forest
The halls where the dragon sleeps
A hard dangerous path in the Misty Mountains
A hidden path with trolls’ footprints
Inside the goblins’ gate
A large dry cave which is quite comfortable
A little steep bay, still and quiet, with an overhanging cliff.
The Lonely Mountain
Long Lake
The mountains
A narrow path
A narrow dangerous path
A narrow place with a dreadful drop into a dim valley
Outside goblins’ gate
A place of black spiders
Rivendell
The ruins of the town of Dale
The running river
A smooth straight passage
A strong river
The treeless opening
The troll’s cave
The troll’s clearing
The waterfall
The west bank of a black river
The west side of Ravenhill
A wooden town in the middle of Long Lake

Common words (tokens) that ChatGPT found (here shown stored in DATA statements):-

800 DATA “the”,”with”,”river”,”forest”,”place”,”gate”,”path”,”dark”,”passage”
810 DATA “black”,”goblins'”,”narrow”,”gloomy”,”land”,”green”,”where”,”comfortable”,”dungeon”
820 DATA “elven”,”king’s”,”bank”,”great”,”halls”,”clearing”,”and”,”empty”,”lonely”
830 DATA “mountain”,”dangerous”,”mountains”,”cave”,”long”,”lake”,”town”,”troll’s”,”west”

…and the resulting location descriptions with indexes inserted representing the word token (this was also generated by ChatGPT):-

900 DATA Beorn’s house,01 Bewitched 13 04,A big cavern 02 torches along 01 walls,A bleak barren 14 that was once 15,01 cellar 16 01 king keeps his barrels of wine.
910 DATA A 17 tunnel-like hall.,A 18 dungeon in 01 elven king’s halls.,01 18 stuffy 09,01 18 winding 09,01 east 20 of a 10 03
920 DATA 01 elven king’s 22 halls,An elvish 24 02 levelled ground 24 logs,01 25 04,01 05,A 05 of tangled smothering trees
930 DATA 01 05 road,01 05 road,05 03,01 front 20 of 01 Lonely Mountain,01 20 to Mirkwood
940 DATA A 13 25 14 02 dreary hills ahead,01 goblins’ dungeon,01 22 03,01 15 05,01 halls 16 01 dragon sleeps
950 DATA A hard 18 20 in 01 Misty Mountains,A hidden 20 02 trolls’ footprints,Inside 01 goblins’ 20,A large dry 31 02 is quite 17,A little steep bay, still and quiet, 02 an overhanging cliff.
960 DATA 01 Lonely Mountain,Long Lake,01 mountains,A 12 20,A 12 18 20
970 DATA A 12 04 02 a dreadful drop into a dim valley,Outside goblins’ 20,A 04 of 10 spiders,Rivendell,01 ruins of 01 34 of Dale
980 DATA 01 running 03,A smooth straight 09,A strong 03,01 treeless opening,01 troll’s 31
990 DATA 01 troll’s 24,01 waterfall,01 west 20 of a 10 03,01 west side of Ravenhill,A wooden 34 in 01 middle of Long Lake

Location Exit Data

Each location has data in this format:-

“01202807506605103”

The first two digits are the location, followed by at least one group of 3 digits.

Each 3-digit block represents an exit, with the first digit for the direction (1 for North, 2 for Northeast, etc., 0 for Down, and 9 for Up) and the next two digits for the destination location number

I had ChatGPT read “The Guide to Playing the Hobbit” and had a go at creating the exit data, but it’s pretty bad – and this needs redoing by hand!

I need to:-

a) Resolve a bug with unpacking the room descriptions properly. It doesn’t convert the token value that lies at the end of a location description string into the corresponding word.
b) Go through all the exit data to check and replace as required (done)
c) Allow the input of directions to include shorthand as well as longhand for the directions (North and N for example).
d) Cross check the common word token replacements. I think ChatGPT has made some mistakes.