you didnt find that denferok. that method has been in the japanese/korean community forever. the first ones who used it in twitch/youtube community were ultragamer then zero and kinata
How aware of this are the Asians? The only fangame I know of requiring jump canceling is Insanity Ultimate, though it's very helpful in fangames that require 1 frame jumps like Pass the Spike.
I'm not good at jump cancelling but I've done a lot of testing to see how it works on a frame-by-frame level. For single jumps, it happens when you press shift, let go of shift, and press it again the same frame. The size of the jump cancel depends on how much later you let go of shift again, but it doesn't work if you let it go again in the same frame. Therefore, the smallest jump cancel occurs if you let it go the next frame. If you let it go then or the frame after that, your head will go less than a tile above ground, so you can jump right under spikes.
For double jumps, a jump cancel can actually be done on any size jump at any point between letting go of shift and reaching peak height. By pressing and releasing shift again, you will slow the kid's ascent (it's an exploit in the programming). In fact, a double jump can be canceled twice if you jump cancel for two consecutive frames. The tiniest possible jump in the engine is when you double cancel a 1 frame double jump (i.e., press and release shift for 3 frames in a row): it's only 3.6 pixels.
Note that platform jumping and water jumping works like single jumps due the possibility of more jumps.
