Designing a computer roleplaying game is a lot like preparing an adventure for your real-life gaming group, except you won't be there to game master in person. You have to send a computer program instead, and it's just not the same. A machine can't tell if the players are having fun. It can't make a monster weaker on the fly if they're having trouble, or fudge a roll of the dice to prevent frustration. Allowing a clever unanticipated course of action just because it's so cool that the players thought of it is simply out of the question.
Trouble is, rule systems for tabletop RPGs are usually written with the assumption that you can. That you will be there in person to improvise wildly when the situation calls for it. An assumption that infamously breaks down when such a game is converted to a digital format. Early CRPGs were widely criticized for having simplistic combat and even worse magic. And in all honesty, how do you implement Tenser's Floating Disc in your average computer game? What do you use it for?
Not that gamebooks, which thrived during the same era (from the late 1970s until the early 1990s), were any more sophisticated, but at least they could store enough text for a proper narrative -- something fans of the genre increasingly expected -- and you could keep a finger or three between the pages as you jumped around. But in many videogames you can't even do that.
I remember an episode from The Flintstones where Fred is watching a game on TV. It's two guys standing in the ring, who take turns hitting each other on the head with a big club. Combat in games can often feel exactly like that.
On the other hand, the most interesting decisions in modern MMORPGs often boil down to, "what precise combination of armor pieces improves the critical hit chance by one percent more for this particular class build". And clearly a lot of people find that fun. Not me.
This is where Battles&Balances comes in. It supports computer games first: every stat has a couple of uses, and they all interact in simple, clear ways. You can easily compare the power of various monsters and character builds, and be reasonably certain they won't be too strong or too weak. On the other hand, every change matters, so choices have meaningful impact, and combat involves lots of little modifiers to take into account.
Last but not least, you can still play the game with dice on a table. That keeps the rules grounded, and easy to visualize: "roll a pair of six-sided dice and add three" yields a number from 5 to 15, with an average of 10.
Battles&Balances is based on extensive research, and has been tested in working roguelikes. Most rules have variations to pick and choose from, and a magic system is included, along with guidelines for making your own. Read on and see what it has to offer.
(You can probably skip this section if you're familiar with the concept.)
Roleplaying games are make-pretend for adults. Who hasn't played mom, or doctor, as a kid? When enough of your pals were outside, you could play Cops and Robbers. And if you were nerdy enough, the latter turned into "stormtroopers and rebels", or "villains and superheroes". The details changed, but one constant remained exchanges like this:
"Pew pew! You're dead!"
"Nuh-uh! You missed!"
"Did not! I'm a good shot!"
"But I'm quick and can dodge!"
"You can't do that! It's cheating!"
"Sure I can!"
More mature players would resolve the dilemma by consciously invoking tropes such as the Rule of Drama, Rule of Cool or Rule of Funny, and indeed that's a popular way to play especially on forums or chat, called freeform. But sometimes you really want to keep track of the details ("did I fire five shots, or six?") to balance out the good and the bad. Which in turn requires some calculations, and dice or cards to spice up the play while still keeping it fair.
That's really all an RPG is -- not how they came to be, but what they grew into. On the computer, they preserve the sense of adventure and strategic challenge while adding a dose of instant gratification, along with elements from other media such as books and movies. Either way, making them work well is an art; hopefully you'll find this attempt worthwhile. Enjoy, and thanks.