I've been trying to figure out how to do the shield jump as performed in Dea1h and 666Deadhunter's runs, but it's not really clear to me exactly what's happening, much less how to replicate it. Any explanations or advice?

Hello ! Sorry for the late answer. The glitch can work with any kind of magic but with the shield you are using only one magic and you can try it again and again as long as the shield is active. It's very simple, you just have to press the magic button and then spam the jump button. The effect is a kind of double jump that allows you to reach higher positions.... and break the game. I asked the same question to Dea1h ^^ I didn't understood that it was so easy, practice it a few minutes and it should be good.

Ah, that explains why it wasn't working for me, then! I figured it was going to be more of an issue of pressing jump at the right time than just pressing it a bunch.

Thank you so much!