For jumping against walls, if you don't press the directional key towards the wall when jumping, you can make smaller, more controlled jumps. Anyway, here's the video :
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I'm glad you like this video :)
I'm not a speedrunner in general, but I find myself trying to speedrun a lot of the Trijam games (and I don't know why, I had the intuition that you didn't know this technique and that I had to record this video).
I think it's important for me to play the games that are offered at Gamejam to the fullest. People invest themselves to create them, I find it normal to invest myself when I try their games.