Azure Dreams PS1 Encyclopedia - List of Bugs

by pro_grammar

This is a non-exhaustive list of bugs present in Azure Dreams, grouped by type.

Crashes

Bugs that cause the game to encounter an exception from which it can't recover, or enter an infinite loop.

(Fixable with 'Fix some crashes' option) Attempting to spawn a monster above level 99 by visiting the 99th floor in the second tower or egg-bombing when Koh is level 50+ causes the game to enter an infinite loop.
(Fixable with 'Fix some crashes' option) Gaining between 32,767 and 39,480 EXP (inclusive) causes the game to try to read out of bounds memory and crash.

Softlocks

Bugs where game logic is waiting for some action to occur but it never does.

The minimap, HUD, and camera can still be controlled as normal, but movement or other game actions cannot be performed. The game has logic to detect softlocks which activates after 30 seconds (900 frames), reseting a few variables that track pending actions and letting game logic run for one loop. Issues that are resolved by this are classified as temporary softlocks (time losses) and cataloged below. The issues that aren't automatically resolved are listed here. By holding down the desired button to buffer your input for the once per 30 seconds unlock, it may be possible to escape these softlocks, e.g. by holding Square to bring up your menu and select a Wind crystal to leave.

Feeding a Mazarr seed to a U-Boat that is out of MP causes a softlock because the pending experience gain is never resolved for some reason.
A Salamander (the temporary monster summoned by Fire crystals) killing an enemy off-screen causes a softlock for some reason. The exact conditions to trigger this aren't known.

Time losses (temporary softlocks)

Softlocks that are resolved automatically after 30 seconds.

Throwing an Oleem at a Manoeva that is transformed into an item causes a temporary softlock.
Having a Golem as one of your collared familiars, allowing it to enter its idle animation, pressing (or optionally holding) Select, not taking any other actions for 30 seconds, then taking an action causes a temporary softlock. The Golem is one of two monsters that has an idle animation (the other being Kewne).
Unlike Kewne, the Golem has code to not exit its idle animation when Select is pressed. Holding Select will not zoom in on the minimap as normal, and pressing any other buttons while Select is held will have no effect (except Start, which would soft-reset the game). Regardless of whether you pressed or held the button, Koh will not enter his idle animation. 30 seconds after you first pressed Select, the game will show the minimap in full (if you kept it held for those 30 seconds) and Koh will re-enter his idle animation. You then have one action before the game locks for 30 seconds. If you were facing the Golem and adjacent to it, walking towards the Golem will allow you to walk into the same tile as it.

Game logic

Bugs where the developers clearly intended one thing to happen but something else happens instead (not purely cosmetic).

Note that this only includes cases where the code or context unambiguously indicates that something should behave differently than it actually does, generally due to a mistake or limitation. The first point below is a great example of how the original intention is clear, not just a matter of my opinion.

Each collared familiar with the talent "Strength increased" should raise the damage dealt by Koh's attack and the Flame/Blizzard Sword, Wind Cutter, and unarmed equivalent mix-magic attacks by 1/8, but because the code in question checks Koh for this talent, no increase ever occurs.
This is clearly intended as there is a function that is called for the sole purpose of performing this check, but the aforementioned bug means it always returns the same result, 0. This intended behavior is even referenced in a tip given by a developer in an interview in a strategy guide and can be seen in the GBC game.
Salamanders cannot hit monsters in some circumstances. The exact conditions to trigger this aren't known.
The mix magic of DeoRock, Gaia Shoot, causes water elemental damage despite DeoRock being a wind elemental spell. This affects both the damage calculation and the appearance of the explosion when enemies are hit.
Barongs are supposed to do a rarity check to ensure that you get something exactly as rare as the item you threw in (or less, if it doesn't find one the first four times). Due to a mistake they they check the rarity of the item you threw in against itself, so that check always passes and the item received doesn't take the rarity of the original item into account.
Earning more that 65,535 EXP at once will cause the value to overflow and wrap around to 0, due to the memory location only being two bytes. This could have been improved by at least capping EXP gains at 65,535.
Since evolved monsters and their predecessors generally gain stats at different rates, evolving a Nyuel to a Battnel and then decreasing its level can cause some stats to underflow, wrapping around to 255. This could potentially be applied to other monsters that evolve by feeding them a Leva fruit to delay evolution beyond level 20.
Manoevas that have transformed into Pickets and stolen an item will not lose that item when transforming back due to the Picket being bagged.
This is clearly not intended as reverting the Manoeva by bagging it directly will cause it to give up its item. This can be exploited as Manoevas holding items that transform into Pickets can thow up a copy of that held item while keeping the original.
Although the De-curse scroll removes the curse on equipped equipment that prevents you from removing it, the Cursed status effect which reduces Koh's luck range persists until leaving the tower or using a Cure-all or Healing herb.
Note that there are both status effects and status conditions. The De-curse scroll does remove the Cursed status condition and removing the Cursed status condition does remove the Cursed status effect, but the Cursed status condition isn't applied by cursed equipment, only the effect, probably because this would cause it to be removed automatically after a finite number of turns. Manually setting the status condition does make the De-curse scoll work as intended, as well as show an otherwise unseen portrait of a cursed Koh in the tower menu.
Lifting a familiar and then either choosing to Return/Free it or giving it a Tumna or Roche fruit will mark the tile Koh is currently standing on as no longer containing a friendly unit, as the game marks the tile occupied by the lifted unit as empty despite Koh standing there. The same will happen if a frogged familiar turns back into a monster while Koh is holding it.
The effect of this is that although enemy monsters will still try to hit Koh with spells and attacks, these will not hurt Koh as the game cannot find a valid target. This is not foolproof, as Koh can be hit under certain conditions (Glacier's ice shot, elevation differences?), but it can still be useful in emergency situations.
Only units that are paralyzed, asleep, blind, or out of MP (henceforth referred to as being incapacitated) have a chance to dodge attacks based on luck, despite all other combat-related checks disfavoring these statuses. Since these are all immbolizing statuses, this should apply to only non-incapacitated monsters.
There are two accuracy related checks. The first checks if the attacker is accurate, based on the attacker's accuracy and luck. If a monster is incapacitated, this check automatically succeeds. After calculating the damage roll and whether the attack crits, only incapacitated defending units have a chance to dodge if the defending unit successfully makes a saving throw to dodge, which happens if its "evasion" plus a roll from 0 to the defender's luck - 1 is >= 128 (assuming non-zero luck; zero luck is the equivalent of rolling a 0). Since the "evasion" of all units always appears to be 0 (n.b. this is different from agility, see point below), an incapacitated defending unit would need at least 129 luck to be capable of rolling 128+. This means that in practice this issue has no effect, as the standard monster with the highest luck still only has 100 luck initially.
Fusing units that have been turned into frogs can have a variety of effects. If Hikewne is frogged, it can survive the fusion where it would normally always be absorbed. If both units are frogged then fused, attempting to take out another monster on that floor will fail. If the fused monster is then put away and you once again try to take out another monster, it will come out, but have the appearance and animation of one of the fused monsters. (Video)
Traps and items can spawn in hallways or inaccessible locations on rare occasions. This occurs when the game generates an item or trap room, but then needs to redo the floor layout. Since the items and traps have already been placed, but are not removed when redoing the floor layout, they could be on top of walls, in hallways, or in the void in the new layout.
The vision of Beldo that appears the first time Koh reaches floor 31 will fail to appear if a trap room spawns on that floor. This is because that vision is loaded in the same memory area that is used for traps, and a trap room writes traps to this same memory area. Similarly, special items like the blue collar and healing herb will be overwritten if the floor has an item room.

Graphical bugs

Cosmetic issues that have no effect on gameplay.

(Fixable with 'Fix some minor bugs' option) The Salamander's attack should cause orange particles to rise from it, but since the particle's size is set to 1x1 and they are always sufficiently far from the game's camera due to the camera zoom being set in combat, they aren't shown at all.
Had the developers truly intended these to not be shown, they would have skipped over the CPU-consuming function calls to allocate and animate them, or possibly set a dimension to 0.
(Fixable with 'Fix some crashes' option) Gaining more than 39,480 EXP from a single unit shows a graphical glitch or incorrect text such as "MISS!!".
Rotating the camera while heating an egg in the tower, cancelling the heating before the egg finishes hatching, and then (without turning the camera) walking in the direction that Koh was facing before heating the egg will cause Koh to walk in that direction without turning to face it, making him appear to be strafing or moonwalking. (Video)

Speculation

Places where I suspect something might be intended to work differently, but might have been deliberately made otherwise.

The above added dodge chance uses a value I call evasion, which is always 0, isn't part of a unit's persisted stats, and is only used for the added dodge chance explained in the above point. However, the game does have an unshown stat called agility which is tracked but never used, and which would be a much better fit for this role assuming the above point were also fixed.
Each monster has its own initial agility value and agility growth value. The game dutifully tracks this when leveling up or down as part of a monster's permanent stats, meaning they persist when leaving the tower. The game even increases this stat by one each time the unit consumes a Mahell seed.
Nevertheless, the stat is never used. It seems likely that this was intended to be used for either evasion or possibly turn order. It's possible that it goes deliberately unused for dodging as high agility monsters (such as the Nyuel) would always dodge above level 51, unused for turn order due to complications in how that is determined, and unused for things such as the monster racetrack due to the game-breaking potential of having an overly-fast monster.