How would somebody use hinge joints to make a stickman platformer character walk?

I do not have a draft. And I really wonder if this is the right category for this. But I’m curious about procedural animation, or whatever it’s called. I know it would involve a stickman and hinge joints and I just wonder if and how it would be possible to animate a stick-person who is made up of independent joint objects, without every single object of him – or any of them – being freely swinging, but all of them being as controlled in their animations as real human limbs. If this is possible how? I expect the answer to be very complicated, but try to keep it as simple as possible.

I do realize that Spine has the same effect, but it’s expensive, and GDevelop already had a perfectly good system before Spine was added that seems to do exactly the same stuff.

Okay, so I got smart and decided to test it out. Yes, it is indeed very, very complex, and for each animation, I have to plan the rotation of every single joint, quite literally, to the smallest degree. Now I think I understand why Spine would be the better option, and why Melon playground was such a slow, high-usage game.