Hará unos quince años estuve en un grupo creativo con la intención de desarrollar un videojuego de rol. Aquello quedó en nada, pero compartí en el foro que usábamos unas reflexiones sobre diseño de juegos de rol.
Entonces estaba ya pensando en escribir mi propio juego de rol, así que algunas de las ideas que reflejé entonces se trasladaron a Sagittarius. Reproduzco el texto, en inglés, tal cual lo compartí en su día.
These are my random thoughts about designing an RPG system. Feel free to discard any or all parts of this rant.
RPG systems are concerned primarily with three issues: character creation, character improvement and character interaction with the world. The latter includes things such skills, combat, magic and a bestiary. It is important to develop all three consistently, so the game will run smoothly and players won’t complain for inconsistencies or imbalances.
Characters are defined physically and mentally by a certain set of attributes. Many can be used to reflect different features, but only four are actually needed: strength, agility, intelligence and willpower. I hope these terms are self-explanatory. More can be added, like quickness, luck, endurance, appearance, charisma, hit-points, if we like a particular feature to be prominent.
The way to assign numeric values (randomly or by distributing points) to these attributes is hardly more than a matter of taste. Certain circumstances, like race, gender, culture, age, profession, training or illness may influence the attributes, either at start or during play. But the important thing here is to define the range of values that a player’s attribute can take; that will influence the skill system and the values of the creatures described in the bestiary.
This is commonly referred as the experience system, or how the character improves as the game flows. If we pursue a realistic system, it is necessary to have two things in mind: that one can learn, improve skills or increase attributes in many ways, and that different skills require different amounts of time and effort to master.
A character may improve through learning from teachers, through training him/herself or through hard experience. The first method is the fastest and more efficient, provided the teacher is competent, but in any case learning takes time and effort. Optionally, the system may make learning easier for characters with high values in intelligence and willpower.
As I said, time and effort requirements vary for each skill. Riding a horse competently may require a few months of training, while learning a new language can require a full year of immersion. Furthermore, the requirements vary also with the level of competence. One can learn the basics of smithing in a few days, but making a living from it would require extensive apprenticeship and achieving mastery can take the whole life, if it is achieved at all. In fact, when you have exceeded the standard level in a skill, continuous training would hardly improve it, but rather would allow you to keep that level; otherwise you will go back to standard levels.
Attributes may also influence the maximum level a character may achieve in a skill. If you are not intelligent, you will hardly make great progress in mathematics, but if you are strong and agile, you can become a good swimmer. At the same time, training a skill may also help to increase a related attribute.
Character interaction with the world
The number and scope of skills is for the most part a matter of taste. The larger the number, the smaller the scope of each skill should be. A larger number of specific skills should be present in the fields we want to focus the game on. If the players will fight regularly, then having one skill for each type of weapon would make sense. If the game will have an strategic component, then diplomacy, administration, logistics or military tactics can be useful skills. As a rule of thumb, before adding a skill, first think if it would of any use for the player in the context of the game.
When and how skills are tested for success is another subject for discussion. A test should be demanded when there is a possibility of a meaningful failure. I mean, that failing will have dramatic consequences. If an expert thief is trying to pick a lock but she has all the time to do it, it is pointless to test her pick-locking skill; eventually she will unlock it. But if she has to do it in a few seconds before an alarm sets off, then a test is in order. Note that as your skill level increases some tasks that were challenging at first may become trivial.
The exact method of testing is, again, a matter of taste. The numeric values of a skill and a related attribute may be combined to determine the number that has to be obtained in a random procedure, modified by the circumstances of the test.
I will exclude firearms from this discussion.
The three most important factors deciding a fight are training, equipment and morale.
Trained fighters have a decisive advantage over untrained people; they know how and when to strike a blow or defend. It is of much less importance in which specific weapon you are trained. In fact, an expert swordsman can pick a dagger, axe or spear and offer a challenge to any opponent. It may even be enough to have one single skill for melee weapons and another for missile weapons, but again, that the depends on the focus of the game.
Usually, the heavier the weapon, the more damage it does. With armour and shield, the larger and more resistant ones also tend to be the heavier. There is a marked difference between metal and non-metal armour. Only powerful missiles (such bolts from a crossbow) have high chances of piercing metal armour at certain distances. As a counterbalance, heavy fighters tire sooner and move slower than light ones.
Horses are usually not well portrayed in RPGs, or are not present at all in CRPGs. In combat, the main advantage of a horseman is speed. He can move into the combat or away from it faster than the infantryman. This can be exploited in several ways: the knight may carry heavier equipment, but still be faster than his enemy, or he can resort to harassing tactics, striking then moving away, then striking again. The horse also provides extra impetus when charging, but apart of this, fighting from the saddle is actually difficult and the horse itself is vulnerable.
Missile weapons are actually much more efficient when used en masse, against a mass of enemies. For a single bowman, hitting a single moving target several meters away is extremely difficult. The most difficult task for a marksman is estimating range to the target, and thus the angle at which to launch the missile.
The third factor in combat is morale, or the will to fight. Only in rare occasions are people willing to fight to death, and in most cases, if faced with overwhelming odds, seasoned fighters will panic and flee. This may occur even at the first charge. However, untrained or poorly led combatants will typically have lower morale than veterans and fanatics.
The magic system depends heavily on the setting and the story. If it is expected that the player would have to use magic regularly, then a detailed system which offers several options would be appropriate. In any case, powerful magic must be counterbalanced by restricting its use in some way. Conjuring spells may drain energy from the character or consume valuable ingredients.
The typical interaction with NPCs in an CRPG is reduced to help or give them valuable items, in exchange of a reward or an increase in the player’s reputation. In reality things are rather complicated by circumstances like gender, social class, profession and family ties, and the personality of each individual also plays a role. There are people who despise those helping them, and only respect people that seriously confront them. Members of the high social class may find natural that lower ones serve them in exchange of nothing. Others may just be willing to help those of good reputation.
Increasing the reputation is only one of a myriad of possible goals in social interaction. Moving to a higher social class, getting in touch with a reliable paymaster, strengthening the loyalty of followers, or opening opportunities for profitable businesses are other goals a character may pursue. It must be taken into account that all may need a lot of time to achieve.
Again, it is a matter of taste which creatures to portray in the game, but their stats should be in proportion to those of the player. That is, large animals should be considerable stronger and harder to kill than a human.
Injury, fatigue and basic needs
Everyone needs to rest, eat and drink regularly, and adventurers are no exception. However these are often trivial matters that do not necessarily need to appear in the game. It would be interesting to account for them in specific situations, like fatigue in combat or food when travelling through wastelands.
The injury and healing systems have a direct impact on the difficulty of the game, and again depend on how the game is focused. If the player will have to fight constantly, then injuries should rarely be lethal, and he/she should be able to find healing easily. If the game is going to be realistic, and most of the fights will be decisive for the ongoing story, then healing may be hard to get and will require resting for a long time.