It's really hard. I played the tutorial and I couldn't get past for the first jump for 6 minutes. After 26 minutes, I still couldn't beat the first level. Absolute madness.
Jokes aside, Cuphead is probably the most unique game of 2017, period; all thanks to it's wonderful artstyle, and I don't think I need to explain that. From what I've seen, Cuphead is a Megaman X-Contra sort of deal, and it's also very difficult. I don't have Cuphead. From the gameplay I've seen, it takes a lot of dedication to beat and I think I'd rather just watch someone flawlessly beat a boss than having to do it myself.