unsurprisingly, different games implement the same mechanics in different ways. in a genre revolving around simple ones those must feel good - however what's perfect for one character or dev will be different for another. i did a study of all the 3D platformers i own to find these different perspectives

higher accelerations increase responsiveness but making them too high can stretch believability. umbra treads this line since he reaches max speed in 1560/9000 = 0.17 seconds - that's half sybil's 550/1600 = 0.34 seconds! (using MaxWalkSpeed and MaxAcceleration in the player blueprints).

max speeds will also change responsiveness but in more of a sweet spot way - high values sacrifice precision while low ones sacrifice the player's patience. max speeds can also change e.g going down a slope or sprinting you'll be able to go faster than you could walking on flat ground.

turning is also involved in this responsiveness balance as characters shouldn't be able to make sharp turns instantly. again, umbra shows how light a character can feel if this is the case. to acknowledge this, most games will have some sort of skid state or animation if you make too extreme a turn. but even for less extreme turns characters like sev and mario have lower turn rates (and accelerations) to sell their heft.

you can't really fall backwards if you didn't start going backwards. but that can make mistakes feel more punishing, so many characters don't change how turning works in the air e.g hat kid. even when this is changed, it's only slightly muted so that you can still

in terms of jump arcs you'd probably assume that all jumps would just follow parabolic motion (a symmetrical curve) like in real life. honestly, if not for this blog post i wouldn't have noticed raz's gravity in psychonauts 2 at the peak of his jump is lower to allow for better precision. while i can understand this, ultimately it may be overengineering a problem which didn't need solving.