MagikarpSC takes tons, if not, probably the most in terms of multitasking in a competitive game. It requires:
High knowledge(there is A LOT to know), High responses, High APM(or speed in general of playing), multitasking of macro and micro to the core, and mistakes can become very punishing.
I've explained some of Melee's technical depth in other posts above, and I don't really wanna explain that again. Mistakes in Melee are so punishing that in many matchups a grab at 0% means death, barring a mistake.
MagikarpI'm not saying melee doesn't have a lot of those, but I'd definitely say it doesn't require as much multitasking. In the end it becomes "choose a field, two players choose a character, fight". I can understand that you have to somewhat have the field memorize and know certain spots to know about, while also knowing about the enemy character in general and aspects of it.
I don't know enough about SC to be able to comment on the multitasking, but I can say that between movement, punish game, neutral game, learning your opponent's patterns, and adapting to options or playstyles you haven't seen before, Melee has a lot of stuff to deal with. Stage memorization isn't really a thing once the match has started. A bit of the true craziness of Melee can be seen once you think of characters as a tool kit for players to use, not opponents. Sure, characters tend to have different playstyles, but Melee is a game primarily played against the opponent rather than the game. The opponent has options, and your job is to figure out what options they're going to use and/or are using and how to beat them with the tools at your character's disposal. The reason bad characters in Melee are bad is because their toolkits are missing important pieces. Imagine trying to build a house without a hammer.
MagikarpBut most players at the highest level already know about that and have it embedded by the time the match starts
Sure, top level players have a much more innate understanding of the game than some random, but it doesn't change the fact that your opponent can surprise you. Melee (as with other fighting games) is kind of like rock-paper-scissors. If the best option for my opponent to do is rock, I should obviously pick paper, right? But the problem is that if my opponent knows this, he can pick paper and beat me. Also sometimes paper beats scissors and rock-paper-scissors is much simpler than Melee, but there is no way to always win at Melee, and there's definitely not a way to learn this subconciously.
MagikarpQuake is a lot different from a 2D-like fighter game.
I couldn't agree with you more, and it's even harder to make a direct comparison between Quake and Melee than it is to make a comparison between Starcraft and Melee. But I'll try.
MagikarpQuake requires aim(important), movement(in a different way from melee), knowledge(this knowledge is different), predictions, hearing(hear item pickups/weapon sounds/movement), and one of the most important: item timings.
So let's break this down into categories. I'm gonna list a few aspects of Melee and try to compare them to aspects of Quake. The neutral game in Melee is similar to all of the things you've said combined besides aim and movement. At the base level, both games' neutral game is all about taking the information you have and applying it to what your opponent has been doing or is known to do. I don't think these are really comparable, as they're both kind of like a weird, complex version of rock-paper-scissors, so I'm gonna just call that part a tie. We're going to compare the movement from Quake to the technical demands of Melee. I feel like Melee is much harder than Quake from a purely technical standpoint. (I'm not including aim) Aim in Quake can be compared to the punish game and defense after you get hit combined. I think Quake takes the cake on this one because once the opponent is in an advantageous position in Melee, gameplay is mostly about damage control rather than trying to kill the opponent. Overall I'd say that Melee and Quake are very similar in the rock-paper-scissors department, although in Quake you can compensate for a lacking neutral (prediction and item timings) with a strong punish game. (ridiculous aim) I'd say this makes Melee a bit harder since you have to be extremely proficient in all three facets of the game (neutral, punish, and technical) to be successful. I'm not as knowledgeable in SC and Quake as I am in Melee, however, so please let me know where I'm wrong.