@Kage it is working, what you're seeing there is most likely a problem on the events of this example.
It seems like it failed to switch the palette, so it's using the first one that was loaded, which was Kirby's palette.
As long you load the correct palette texture it should work, so check the example again.
An just to make sure you're not using a old broken example, here's the one that works here:
oh, I figured it out, sorry for the confusion. I have one more stupid question: since I'm developing a fighting game (Mortal Kombat), this shader would be perfect for me with the FLIP function, is it possible to add this?
Hmm, I can add it, sure, but be aware that flipping the sprite won't change the actual collision mask, so you most definitely need a separated object for hitbox or that trick of embedded hitbox.
I'll see if I can add the flip today.
Have you got it to work with your MK sprites? Cause seems like a lot of colors