this is totally random bcz of the ragdoll physics

but there's atleast 2 levels, where you can use it with 100% chance:

Level0 - just press space since start and walk immediately forward until ure legs will not stand together (https://imgur.com/C0n5hqA), then release space and you will jump with increased power. Level6 - press W+D and space immediately and walk untill you get the same pose (https://imgur.com/undefined), release space and shoot in robot behind at right.

the reason in this weird legs behavior is that one leg skips a step and repeat it at the next one with the other leg doing her own step at the same time.

the cause of this leg step skips should be incorrect spawn of main character in this levels. the character falls from a height in these levels.