I dunno if it's just me, but I SWEAR the dragon boss in world 2 of Cuphead is a difficulty spike, because I died nearly 100 times and it took me at least a combined time of an hour to an hour and a half to beat him. His third phase was what got me 90% of the time, especially with those fire bubbles that make four-way fire balls when popped and can come in rather suddenly at times.