There are twelve illusionist spells of 1st-level in AD&D, the same number as there were in OD&D. Two of these spells (audible glamer and dancing lights) are new to the list, replacing ventriloquism and mirror image.
Audible Glamer: Like the 2nd-level magic-user spell, it creates whatever sound the caster desires. The m-u description says that, when cast at 3rd level, it creates a sound volume equivalent to four men. Illusionists can cast the spell at 1st level, so I need to figure out if their spell volume begins at four men, or if it starts lower. I'll probably start them at four, just to make the spell more useful. The illusionist version of the spell lasts longer (3 rounds/lvl as opposed to 2), is quicker to cast (2 segments as opposed to 5) and requires no material components.
Change Self: The caster is able to change their appearance to that of another man-shaped creature, although they can't make themselves look more than 1 foot taller or shorter. The illusion can affect their equipment as well.
The OD&D version of the spell says that the user can appear as a creature of the same general size and shape, which I actually like better. It makes the spell useful for dragons and other non-humanoid spell-casters. The duration in OD&D was 10 rounds + caster level + 1d6 rounds. In AD&D it's 2-12 rounds + 2 rounds/level. Those durations seem a little needlessly complex, but I suppose it's to inject a little bit of uncertainty as to when the spell's going to end.
Color Spray: This spell creates a cone of clashing colors that affects 1-6 creatures within its area. Creatures with HD equal to or lower than the caster are struck unconscious, those up to 2 HD higher are struck blind, and those 3 or more HD higher are stunned. Creatures with more HD than the caster has levels receive a saving throw, as do any creatures with more than 6 HD. Its material components are a pinch of powder or sand colored red, yellow and blue.
There's a line in the spell that seems contradictory to me: "The spell caster is able to affect 1 level or hit die of creatures for each of his or her levels of experience". If that's the case, how would the spell affect creatures with more HD than the caster's level, as detailed above? Is there something I'm missing here?
The OD&D version might shed some light here. It affects 1-6 levels of creatures, rather than 1-6 individual creatures, with the number of levels equal to the caster's level. The target is randomly assigned, with fully affected targets receiving no saving throw and any partially affected one getting a save (with a bonus for every HD unaffected). The spell couldn't affect creatures with more than 6 HD at all. It also couldn't blind or stun targets: it always knocked them unconscious.
I don't know, I can't get that line to make sense. Perhaps it works like the OD&D spell, only partially affected creatures are blinded or stunned rather then getting a saving throw bonus? However it works, the OD&D spell was more clearly explained.
Dancing Lights: Works exactly like the 1st-level m-u spell, creating 1-4 balls of light or a glowing, man-shaped figure.
Darkness: Works like the 2nd-level m-u spell darkness 15' radius, creating a globe that light and infravision can't penetrate. The illusionist version doesn't last as long as the m-u spell (2-8 rounds + 1 round/level, as opposed to 1 turn + 1 round/level) but it's quicker to cast (1 segment vs. 2) and requires no material components.
The OD&D spell was said to be the same as that cast by "Anti-Clerics," and was defined only as an opposite of light. That gave it a similar radius of 15", and a duration of 6 turns + 1/level. That could be a super-long duration, but as ever in OD&D it's hard to say if this was intended to be turns of ten minutes or combat rounds.
Detect Illusion: Allows the caster to know an illusion for what it is, and to allow others to do so with a touch. Its material component is a piece of yellow crystal, glass or mica.
The OD&D spell was the same, although it said nothing about bestowing the ability upon others. It had a range of 6" (1"/level in AD&D) and a duration of 3 "turns" (3 rounds + 2/level in AD&D).
Detect Invisibility: Like the 2nd-level m-u spell, it allows the caster to see invisible, astral, ethereal, hidden, or out of phase creatures and objects to a range of 1"/level. The illusionist spell is a bit quicker to cast (1 segment vs. 2).
The OD&D spell was named detect invisible, and detected invisible creatures and objects. It mentioned nothing about those that are hidden, astral, ethereal or out of phase. It had a duration of 6 turns (5 rounds/level in AD&D) and a range of 1"/level (same as AD&D).
Gaze Reflection: Creates a mirror-like area around the caster that reflects gaze attacks back upon the gazer. Extremely useful, but it only lasts 1 round.
The OD&D spell only mentioned reflecting the gazes of basilisks and medusae. It was given a range of 8", whereas in AD&D it's presumably effective at whatever range the creature's gaze has. It lasted 1 turn, which might mean the same thing as the 1 round duration in AD&D.
Hypnotism: With gestures and a droning incantation, the caster can hypnotise 1-6 creatures and give them a suggestion (like the spell) that they will follow for the spell's duration (1 round + 1/level). Suggestion as a spell in its own right only affects a single creature, so hypnotism is stronger in that regard, but it has a far shorter duration (minutes as opposed to hours).
The OD&D spell worked like charm person, with a penalty opposed to the target's saving throw and the requirement that they look into the caster's eyes. A completely different spell, basically.
Light: Works like the 1st-level m-u/cleric spell, creating a globe of light that illuminates a 2" radius. It has the same specs as the m-u spell exactly. It has half the range of the cleric spell (6" vs. 12"), a duration that's shorter by an hour, but a quicker casting time (1 segment vs. 4).
The OD&D spell created a 3" diameter illumination, rather than the 4" of AD&D.
Phantasmal Force: Like the 3rd-level m-u spell, it creates a silent illusory creature or object that can damage foes who believe it is real. It has a shorter range than the m-u version (6" + 1"/lvl vs. 8" + 1"/lvl), and a smaller area of effect (4" square + 1"/lvl vs. 8" square + 1"/lvl), but a quicker casting time (1 segment vs. 3).
The OD&D spell, called phantasmal forces, mentioned nothing about the illusion having no sound. It had a range of 24", far longer than most AD&D casters will ever manage.
Wall of Fog: Creates a fog in a 2"/level cubic area that obscures sight. It can be dispersed by a strong breeze. Its material component is a pinch of split dried peas.
The OD&D spell mentioned nothing about strong breezes. It had the dimensions of a wall of fire, which meant a flat wall 6" wide and 2" high, or a 3" diameter cylinder 2" high. Its range was 16", far higher than AD&D's 3". No duration was given.