How do you get the IJ consistently? I got it twice on my casual, but now I want to run this game and was wondering how to get it. TIA!

Edit: Mainly talking about level 2 and the final level.

i can get it pretty consistently by jumping right under a gem.

Yeah you can press Jump a couple frames before collecting a gem from below (which is easier than it sounds) or by standing on a disappearing platform as it disappears. Those are the 2 that are currently in the run, but there are many more, like taking 2 hits of damage in the same frame Via Volcano and such.