Magic in Tunnels & Trolls is a fairly standard (though innovative back in ’76) system of individual spells that cost spell-points to cast. In earlier editions, your spell-points were your STR, now they’re your WIZ, which seems to me widen the range of possible character types quite a bit. The names of the spells are whimsical, like “Take That You Fiend!” (the basic magic blast spell), “Dis-Spell”, “Oh, Go Away!”, which some people find a bit off-putting, but the spell effects are generally straightforward: do damage, turn invisible, heal wounds, and so forth. Not always: “Troll God’s Blessing” causes a big club to appear over the head of the target and bash it, but if that kind of thing is a problem for your players you can easily substitute more “serious” flavor text. Spells range in level from 1 to 13 (or more, I suppose, but that’s as far as the books go). Wizards begin with all the standard 1st level spells, and learn new spells from the Wizard’s Guild, by paying 1000 GP per level of spell. Spells can only be taught by direct instruction (presumably by casting the first level Teacher spell until the Wizard succeeds at the SR to impress it in his mind). Casting a spell requires a Saving Roll against the level of the spell, which should mostly be a “gimme” except for very low level casters or when trying to cast a spell at a higher level than you’ve reached.
That brings up an unusual feature of T&T magic. While spells have a minimum DEX and INT to cast, they aren’t restricted by the level of the caster. A 1st level Wizard can attempt to cast a higher level spell, it just requires a harder Saving Roll and higher stat minimums. A 1st level spell requires 10 INT and DEX, a 2nd level 12, all the way up to 100 for a 13th level spell. Many spells can also be cast at higher level than their minimum in order to ramp up their effects, e.g. Take That You Fiend! costs 6 WIZ and does damage equal to the caster’s INT at 1st level. If a Wizard with INT 15 casts it as a 2nd level spell, it costs 12 WIZ but does 30 points of damage, as a 3rd level spell it costs 18 WIZ but does 60 points of damage, etc. Whether a spell can be “Powered Up” and the effects of doing so vary depending on the spell.
Spell costs can be reduced in a variety of ways. If you’re higher level than the spell you’re casting you get a discount, with a bigger discount the higher level you are compared to the spell level, though there’s a minimum cost of 1. You also get a discount for using a “focus” such as a wand or ring. In fact, the primary purpose of wands and staves in T&T is as spell foci rather than bearers of independent spell effects. Specialist Wizards get to cast all the spells in their specialty at half cost, but can’t cast spells outside their specialty at all. WIZ recovers fairly quickly, 1 point per ten minutes of non-strenuous activity (no combat or running, but you don’t need a lie-down), but high-level spell can still take hours to recover from casting since they can cost 30, 40, 50, even 200 points to cast (for the 13th level “Born Again” spell).
An even more unusual feature, and one that’s apparently new and somewhat controversial, is that spells cannot be directly cast on any target with a current WIZ higher than the caster’s. That means that not only are Wizards unable to affect more powerful wizards (at least until their targets have expended enough WIZ to make them weaker), but Wizards may find themselves unable to bespell Warriors and monsters if they have built up their WIZ. Monsters typically have WIZ equal to 1/10 of their monster rating, so a dragon with MR 500 has quite a substantial barrier against direct-effect spells. Wizards who attempt to cast against a target with higher WIZ get a “bad feeling” that lets them stop before they actually waste any of their own WIZ.
I’m not entirely sure what I think of this. On the one hand, I certainly see roleplaying possibilities, particularly since spells that indirectly affect the target (e.g. its clothes, or by affecting the ground under it, or drop something on it) are possible regardless of differences in WIZ. It also gives magic a very otherworldly feel, not at all equivalent to simply having a laser pistol or even crossbow. On the other hand, since WIZ amounts vary round by round in combat based on the spells the magic users are casting, it might become something of a pain to track, and even if it didn’t you could potentially lose a lot of actions to “bad feelings” when your estimates of the current WIZ of your opponent miss the mark. On the third hand, it adds another tactical dimension when unleashing a huge spell at the beginning of combat can render you vulnerable to lesser magicians for the rest of the combat, and I’m in favor of increasing the number of tactical decisions, at least in moderation. As with other things T&T, I really have to see how it plays out in practice.