Bug or Feature? That is the Question.

Last time, we looked at how Moonstone AGA started and some of the technical challenges behind the remaster. This week, we’re looking at something Moonstone players probably remember almost as well as the gore: the bugs.

We love Moonstone regardless of its quirks. But playing it meant learning a few precautions: which situations to avoid, which objects not to touch, and when to hope your Amiga would let you finish your adventure.

None of this takes away from what Rob Anderson and his small team achieved. Moonstone combined animated combat, a turn-based world, multiplayer, character progression and an inventory system within very tight limits. Rob has explained that development was expected to take a year but took two, and that third-party testing was very limited and only came at the end.

So what are those bugs? Well, they come in many forms.

One of our “favourites” was the Moonstone itself. Taking it from inventory could freeze the game and trigger a Guru Meditation. For quite a long time, I honestly thought maybe this was intentional.

Finding Out What Actually Went Wrong

For Moonstone AGA, remembering a bug is only the starting point. We also need to understand the code, reproduce the problem when possible, and ensure the fix doesn’t alter the intended gameplay. Some discoveries have been surprisingly small, like collision checks or game inconsistencies.

When the Manual and the Game Diverge

Not everything we found was a crash or a broken animation.

The manual warns that a cursed Scroll of the Wyrm can turn the dragon against its caster. But the original activation routines we examined contain no such curse. We’ve fixed this; Moonstone AGA now follows that warning, using a 25% risk. We chose that percentage to make it a real gamble, as the manual doesn’t specify one.

The manual says that a Moonstone gives you twice as much health during its matching moon phase. In the original Amiga game, it makes your attacks twice as powerful instead. Our version follows the manual: you temporarily gain twice as much health, so you can survive more damage, while your attacks keep their normal strength.

Animation Glitches

There were also some graphical glitches; for example, the Trogg dying with blood flowing out of its body had an animation offset, creating a slight jump. This has been solved in the AGA version too.

A Hit or a Miss?

Sometimes, a knife thrown away from an enemy could still damage it. The collision routine checked the wrong pixel position when the knife was mirrored, allowing a throw in one direction to register a hit in the other.

The opposite could happen near the edge of the screen: a strike that should connect could miss a partially off-screen character because another check misread its coordinates.

We corrected both checks in Moonstone AGA. At last, the code will play fair.

The Never-Ending Fire

Sometimes, the dragon’s flames disappeared, but the sound kept going. Apparently, burning you alive wasn’t enough; it had to annoy you afterwards too.

We found two possible causes: the game could try to stop the wrong audio channel, or an interrupted fire-breathing animation could skip the instruction that stopped the sound altogether.

The fire sound now stops when the flames disappear. The dragon’s attack, damage and timing remain unchanged but it’s still just as deadly.

Even Death Had a Few Bugs

During a Ratman’s strangulation attack, a knight with no health left could still respond to the escape command and stab it. Another issue with a successful escape: if the stab killed the Ratman, the game immediately replaced the stabbing animation with the release sequence. The damage happened, but the actual blow could disappear before you saw it.

So, how many bugs have we fixed so far?

Our documented list currently stands at 13 distinct original defects, plus two manual-based gameplay corrections. There is still more to investigate. And some unpleasant things are intentional; for example, Ratmen’s disease is staying. The aim is to keep the Moonstone we loved while removing the accidents that could end an adventure too soon.

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