Those are all from the same franchise, whereas this is some group of people who are blatantly ripping off a gameplay style, assets, and animations from a major indie game that had a lot of time and work put into it
Sure the game may be good, because it's literally just Cuphead re-skinned, but it's also still blatant, scummy, plagiarism that these developers are asking for money for
brother you can't rip off assets and animations when you literally have to draw every single frame.
Also speaking as someone who's from the industry: Everything is 'stolen' in one way or another, thats why we call it 'borrowing' in the industry, because the concept of 'stealing' an idea is loving stupid, there is so much more work that goes into animation and game design then just the overall idea. Your favourite game/show probably stole most of it's design, content, and story structure from what came before it. I mean forget by this logic Cuphead 'stole' from 1930s cartoons.
This isn't stealing, it's capitalizing on a fad. Personally one Cuphead is enough for me, I don't need another but it's very clear from looking at the gameplay that a lot of hard work and dedication went in to this game.