I'm hoping to hear what you like about well-written NPCs in parser games/text adventures.

Of course, there are always the standard/obvious points that NPCs typically ought to hit:

• Talk to/Tell/Ask commands available
• The NPC doesn't move around pointlessly
• Each NPC serves some purpose
• No NPCs that do nothing except to help the player solve only one puzzle
• The NPCs have some characterization and sense of voice in their dialogue
• The NPCs have their own goals and motivations as characters

But of course, these are merely basic points. I would like to hear from everyone what makes an NPC not just acceptable or good but effective and likable. I've been playing the XYZZY awards 'Best NPC' category games to get some sense of the idea, but I'm not sure that I can articulate what it is that makes outstanding parser game NPCs outstanding as I'm just too new to IF.

(But it does seem that the best NPCs always seem to have some kind of unique implementation about them that makes them unique.)

The reason I ask is that I am currently building my first longer, more serious game (I've built some really silly duds under another username, but those are of no importance/don't matter) and it is going to feature a handful of NPCs who I hope will be the strongest part of the story. As such, I don't want them to feel placid or flat.

I'd be glad to hear what anyone has to say.

I would just add giving NPCs some bit of background, but in general terms, it seems you already know how doing it . I suppose your challange now would become dealing with lack of ideas or just overthinking, because you seem to be very ready for character creation.

Also look at articles about characterisation when writing novels. Most of the same ideas will apply.