Just one thought, after seeing some comments about the Bard's Tale remaster and the changelogs for the patches:

What are the worst bugs in video games that do not actually interfere with the game's playability or stability? In other words, the bug must not make the game (or a part of it) unwinnable, and must not lead to a crash or softlock.

Also, what games have a lot of bugs of this sort?

(Note that this topic is about bugs that make the game less fun; bugs that can make the game *more* fun (like exploits and sequence breaks) are not what this topic is about.)

The example that comes to mind is actually the DOS version of Bard's Tale 3,.which has a whole bunch of bugs. The most serious of these bugs prevents enemies from using their special attacks; dragons don't breathe fire, slayers don't slay, magic-eaters don't eat magic, and the final boss won't use its special ability, making fights rather boring. (That version has many other bugs, like DIVA not healing your party as it should, monsters appearing in the wrong places (sharks found outside of water), random encounters being more frequent than intended, and Harmonic Gems being much rarer than they should be.)

So, what other examples can you think of?
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In the mafia forum game, a bug can cause a reply not to appear and then when you try to remedy that, it merges both posts. Pretty nasty.

The Steam version of Manhunt is filled to the brim with bugs that render the game basically unplayable (for instance: the very first door you come across -or any door for that matter- won't open). Thankfully, there are fan patches that fix most issues.

However, one really annoying bug remains: Occasionally, the game will play an in-game cutscene. Every once in a while, a very prominent background sound that is played during this cutscene. After the cutscene finishes, the game won't end this ambient sound. Instead, it will start looping this sound over and over. This is particularly grating in a level where the cutscene shows a guy watching German porn on TV. After the cutscene ends, you're treated to an endless loop of "Ohhh ja! OHHHH!!! Das tut gut, ja!!!"

Seriously??? How on earth did that pass QA?

Lol, what QA? We're talking Steam here.

They put a warning label on the store page that reads that the game won't run on anything other than XP and called it a day.

Pool of Radiance: Ruins of Myth Drannor

If you install the game to your c:/ directory, when you uninstall the game it deletes your harddrive. Doesn't prevent you from completing the game - although the game itself being pretty crappy might.

On a related note: the original NWN has some feats and skills that basically don't work, are completely useless, or have no checks in the game to make them a useful choice. Doesn't prevent you from completing the game, but it's annoying as hell to burn skill points or feat choices only to find out later they were a complete waste.

*edit* Applies to some spells as well.

I think all RPG and ARPGs have a few of those.
I swear, I think Devs throw them in to keep people honest, and I really don't have a problem with it. I think it adds more variety and risk to the game.

Maybe they were included as options for user-made modules? NWN was to a large degree intended as a toolset for creating campaigns iirc.
The spells in Albion I mentioned can actually be used by your characters...but you get a bleeping sound (indicating a bug) and there's no spell effect (or it doesn't work like it should), so you just wasted a turn.

Infrequent crashes to desktop? Or occasionally erasing your savegame? It doesn't necessarily make the game unwinnable, just really, really annoying and frustrating. :P

Personal examples off the top of my head would be the PC version of Saints Row 2 (with GotR patch) crashing in the midst of a longer mission (the game isn't saved during those), or the Early Access version of Slay the Spire, a rogue-like-lite, erasing my 2/3 acts through run due to a crash, when I tried continuing after taking a break.

Reminds me of Daggerfall, where there's a bug where a note will get stuck; it's as though, in a system using MIDI, a note-off message was lost. (Does the game use MIDI internally for its sounds?)

With thad said, Daggerfall does have some bugs that impact stability and some that can softlock quests, not to mention out-of-bounds glitches that casual players encounter all the time. Don't forget the Improved Initiative feat in Icewind Dale 2.

Edit: Also, Final Fantasy and its sequel had a bunch of non-working spells. LOCK, TMPR, and XFER do nothing when used by the player (and WALL and AFIR similarly do nothing if an enemy uses them), while LOK2 makes enemies harder to hit. (Anyone who has played remakes of FF1 will remember Steel/Temper being quite useful; in the original this spell didn't work.) Maybe you should plat the original SaGa, where tons of things are broken, but the game still manages to hold itself together. One particularly famous bug involves a chainsaw (actually both a weapon called SAW in FFL and a skill (which a couple enemies do use) with the same name). That weapon/skill will *only* work if the attacker's STR is less than the target's DEF. If you have 100+ STR (quite possible in this game), there are only two enemies that can be affected:
* One is an enemy you are not meant to be able to kill.
* The other is the final boss.

(Incidentally, in SaGa 1, for every stat there's a downside to having it high; high STR/DEF can be a liability when SAW is involved, high AGI makes multi-hit attacks that hit you do more damage per hit (but will help you avoid them), and high MANA means that the MELT and DRINK attacks will hurt you more (MELT is used by slime-family enemies).)

At least you *know* you wasted your turn. In the FF1 examples I mentioned, the spell animation will play, you will get a suitable message, but the spell effect won't occur.

Definitely a possibility for some of them, but there were others that were just flat out broken.

I can't save in The Cat Lady. Not technically game breaking because I could theoretically beat it in a single playthrough but really discouraging.

I think that counts as game breaking.

Technically you can beat ANYTHING in one playthrough. :P