So I'm thinking about psionics in OD&D. I just read over the rules again recently, and it strikes me that just as with their AD&D counterparts, these are less arcane and complicated than people think they are. What the rules are, is poorly stated and very poorly organized--but that's par for the course for much of OD&D. I think I'm going to try a re-wording of these rules. Maybe I'll use the OGL and put it out for use with Swords & Wizardry / Labyrinth Lord.
As with much of the later OD&D additions, the system is very similar to that which eventually appeared in AD&D first edition, though simpler in execution and more arcane in explanation.
In any case, the basic system is pretty easy: at char gen, roll % dice if you're human to see if you have psionic potential. 91-00 means you do. Thereafter, you have a 10% cumulative chance each level to get a new psychic power. A second roll on a psychic potential chart at char gen modifies this base 10% chance/level. Each psychic power you get costs you some base class abilities.
Along with psychic abilities come psionic attack and defense modes which are used in direct psychic combat. Essentially, you compare the attack mode against the active defense mode on a matrix which takes into account both sides' total psionic strength (combined attack and defense pools), and the result indicates how much damage to overall psychic power that the defender takes. It's actually a diceless psychic combat system (occasional saving throws notwithstanding), which is interesting in OD&D. Using attack and defense modes costs points drawn from attack/defense pools. When the defender can no longer power defenses, they are treated as surprised/defenseless and the attack is figured on a different matrix, the damage to psychic potential far greater.
The one thing the rules don't specify is what exactly happens when your psychic potential is entirely drained (assuming you don't get an alternate result on the table indicating death, stun, etc.). Are you dead? Unconscious? Stunned? Or just unable to use psychic abilities?
There are some wording issues to hash out--for example, one of the attack modes claims only a single defense can be used against it, but the matrix shows results for three defenses. These are the types of errors that tend to crop up once in awhile in OD&D, however, and are left to the DM to hash out for him/herself. I'd go with the matrix over the text.
Beyond direct psychic combat, psychic powers aren't much different than spells. You spend points to activate them, drawn from your combined attack/defense pool. Each character class has their own list of powers available, split into basic and advanced. Whenever you get a new power, you roll randomly to see what power you get, but you can't have more advanced powers than you do basic.
Psionic strength points recover at varying rates depending on how active the psionic character is.
It actually strikes me that a campaign using psionics could be a great deal of fun to play, and certainly it makes the Aboleth and Mind Flayer a lot creepier. In a world where magic is part and parcel of everyday life, where elves and dwarves adventure alongside humans, horror is a difficult thing to portray for most (though not all) people. The addition of Psionics adds an element of "other-ness" to D&D in the form of a new, random, and little-understood force with which the players must contend.
On the other hand, in a game where everyone is psychic, you could have a really flavorful "street-level supers" D&D game, particularly if you remove psychic combat from the picture and just run with the powers.
A little something to chew on.
That's all folks. I'm out, and remember: Fear not, Ranger, Cavalier, Barbarian, Thief, and Acrobat! That was Venger, the force of evil. I am Dungeon Master, your guide in the realm of Dungeons & Dragons!