>>2391696you could probably do a one stage platformer like mario where watamelon can find a wand/hat upgrade that turns her into watamelon mage or a helmet/sword that turns her into watamelon shogun. goal of the game is to turn into watame no melon (pic related, but player might be led to believe it's regular watame). you have to defeat some holo (botan?) to return to normal for whatever reason
watamage can turn enemies into watame's followers (if you ever see her 3d streams, it's the audience when she's singing, not sure what they're called? watamates?). watame shogun just slices enemies? could also just turn them into regular watamelons if you don't want to model watame's audience
enemies could be whatever. maybe other holo followers (senchou crew, nousagi etc)?