im gonna leave some tips rn
how to get characters:
the yellow powerpuff girl: play blossom in space
the green powerpuff girl: beat the golden sonic minigame the one where hes like "listen to me and i will leave" and survive by hiding in the brown thing
red powerpuff girl: get an a rank in the helicopter minigame
phantom tails: go to the left on the golden sonic minigame and once he stops talking go to the right
the guy with 5 heads: beat blossom in space without getting a cake also pro tip hold a and d and then hold space to glitch under the floor
black red eyed sonic: DONT get an a rank in the helicopter minigame
sister location sonic: beat every boss in world 7
and then everyone one else sorry i kinda got them random so idk