I guess it was a screenshot from its early development with that moon shaped boss, which I've had sitting on my computer for several months, if not a year, if the initial release date was just a week ago. I thought it just came-a-went, but it's pleasing to see something as unique as this, getting well received!
I can't help but worry it's going to turn into a mess like Undertale...
I don't understand this train of thought. Everything has a bad fandom, some worse than others. Undertale isn't even close to being the worst thing ever, yet so many more people are butt-blasted about the game than there are fans talking about it.
Cuphead is going to be fine. Just let that pointless comparison go.