I've spent a bit trying to determine which abilities are of any use for a speedrun. Here is the full list of abilities:

Dodge, Regeneration, Veteran, Perception, Disarming, Winning Streak Elemental, Light, Darkness, Shadow, Witchcraft Berserk, Poison Weapon, Curse Weapon, Weapon Master, Iron Skin, Shadow Acrobat Battleaxe, Great Sword, Archery, Staves Mace, Long Sword, Club, Dagger, Short Sword

Perception doesn't matter as we can just memorize the location of any traps we want to avoid or hidden treasure we want to find.

Disarming doesn't matter because we can just use the unlocking glitch for locked chests, and stepping around traps (or just taking the hit) is faster than disabling them.

Winning Streak doesn't matter as we don't have time to gamble.

All the weapon-group-damage-up abilities aren't that helpful. As far as I can tell, they add 2 points to attack for each ability point. For a lot of the smaller foes, this isn't enough to change the number of hits to kill. For the endgame bosses, 2 is just tiny compared to the weapons at that point in the game. Maybe if you have nothing else to spend your points on.

Weapon Master would be great, but the prerequisite cannot be bypassed with known glitches, so that means we actually have to have three of the non-particularly-useful weapon abilities. Even if we wanted to do that we need ability slots. A pre-built character would take until level 31 (around getting the Maze Toy) to have four empty slots, which is too late to be useful. A custom character could do it at level 21 (blowing the horn) if they spent every ability slot, but I've tried this, and it is very slow.

Dodge sounds like exactly the sort of thing that would be useful for running past enemies, but it doesn't seem to... do anything. I had a save where I let myself get beat up by various enemies with 0 dodge, then tried again with 24 dodge and I cannot tell the difference. Either its not working, or so minor so as to be useless.

Poison Weapon adds damage over time, but we don't really want to wait around for anything in a speedrun.

Curse Weapon is pretty much only useful against the Cyclops, and only if you had really weak weapons. However, weak weapons would take forever still to kill the Cyclops and strong weapons can just kill the Cyclops before its beam attack matters.

Witchcraft is just the magical version of Poison Weapon and Curse Weapon.

Darkness' prerequisite can be glitched past if you wanted to, but it just contains really expansive damaging spells. Elemental does this better.

Iron Skin doesn't help against the endgame enemies because we don't really have time to add in much armor of our own. Against early enemies its probably better to just get more Regeneration.

All those abilities can probably just be ignored. Here's all that's left:

Regeneration, Veteran Elemental, Light, Shadow Berserk, Shadow Acrobat

Usually we take damage when we rush past enemies, and Regeneration means that we have enough hp by the time we reach the next enemies to do it again. Also lets us use mana abilities more.

Veteran lets you level up more (+7-11 extra levels by the end, depending on how early you apply it), which lets you get more hp, mana, and attribute points, which are useful.

Elemental is the main reason a wizard build could make sense. Your damage is not dependent on what equipment you can find, which is good because we don't have a ton of time to find any.

Most of the Light spells are not very useful, but Light 1 allows you to convert redundant mana regeneration into faster health regeneration,

Shadow 1 can stop the green beholders from poisoning you, which is important in a luck build. It can also stop the Cyclops' beam attack. Shadow 13 can freeze enemies that are in your way so you can just shove them aside.

Berserk's give extra damage and extra speed, which is good for quickly killing things we have to kill.

Shadow Acrobat is good, but you have to save up 25 points so you can skip past the prerequisite, and I'm not sure it's worth it.