Sound and Music
Golly, sound in Roguelikes sure is awful. Ever play the Windows binary of Angband with the sound on? Total silence, until you fight a creature. Then a series of odd squeaks that remind you primarily of the sketch in Monty Python where the man plays a xylophone of little mice. Then you kill something, and it's so loud and weird-sounding that you have to turn down the speakers (when did a mushroom patch -- not counting shrieker mushrooms -- go "aaargh" anyway?) We should improve this.
Implementing sound is, of course, an extremely platform dependent thing. The first thing you need to do is construct your generic sound library, usually with three funtions: PlaySound(char *sound) to play a sound, PlayMusic(char *music) to change music, and Silence() to quiet everything. Plus a few support functions like SoundOn(), SoundOff(), and Volume(int vol). Notice that I am suggesting you call the sound funtions with strings. I would go even farther and say you should use strings, but not file endings; so make calls like PlaySound("die") or PlayMusic("creepie"). Let the internal implementation figure out whether playing "creepie" means loading the "creepie.wav" or "creepie.snd" internal resource and playing it over and over, or launching "creepie.mid" in a MIDI player, or even running an MP3 "creepie.mp3". You will thank me the first time you port your program and don't have to change 300 sound references.
You also want to design your sound library to react gracefully if the sound isn't found. In my games, if I call PlaySound("blowgun") and I don't have a blowgun sound, PlaySound just doesn't make a sound -- but no errors. That way, I can add sounds to the code without worrying if I have the actual sound yet. And I can do a simple text search to see what sounds I need.
The rules for good music and sound in Roguelikes are the same as for every other game: they should reflect the mood of the game, they should have a common theme, they should be at appropriate volumes (dragon breath should be louder than a squeaking mouse, but neither should be so much louder than the music as to force someone to turn their volume down too low). There should be lots of sounds -- better 150 sounds at low-quality than 50 high-quality ones (you won't notice quality in a mouse squeak anyway). And especially, there should be no annoying or out-of-place sounds. One dead dragon squaking like a mouse, or worse still a "Silent Warrior" giving a big death scream and you feel very silly. If you are storing your monster and item information in text configuration files (a very good idea), save what sounds they make there as well. The important thing is that one bad sound ruins all the good sounds, so if you are in doubt, leave the sound out (that wasn't meant to rhyme).
The best way, of course, to appreciate sound is to find a good example. If you want good sound from a game, go for Star Wars -- note the wonderful way they change background music to match scenes. You can do that in your game -- switch to a darker sound in lower levels or an excited song at low hit points. Be VERY CAREFUL to provide a minimum song length -- a song should play at least 30 seconds before shifting to another one. Otherwise, imagine a combat where you keep getting hurt and quaffing Healing potions -- what would that do to the sound? Or going up and down between two levels?
But the best example of sound in a roguelike by far is Mission Thunderbolt. Good luck getting it: AFAIK it's for Macintosh only, and not for free, but if you are lucky enough to get a copy you'll find a good, science fiction roguelike (I like the potions -> pills transformation myself). But the beautiful sound! Crunches, mumbles, a wicked "hee-hee" when your stuff gets stolen, weird electric noises, etc. Useless for a fantasy game, but fits a sci-fi game perfectly.
We like to think in Roguelikes that the game mechanics alone create an atmosphere. The stereotypical "D" that looks in our imagination more like a dragon than the best of computer art is wonderful, but where is the replacement for the music? I'm sure plenty of people who play roguelikes in text mode still put on some adventurous music in the background, and giving your own atmostphere to a game can only be a plus. In the end, the best advice is exactly that for graphics in a roguelike: it can be a big plus if it is good, atmospheric, and doesn't distract you too much from gameplay; but if it fails to be any of these things (if it is low quality, inappropriate to the atmosphere, *or* takes programmer time or CPU/memory availability away from gameplay) then leave it out.
James Burton [firstname.lastname@example.org]