From the 1920's and 30's themes, the sweet jazz music, and a shlewww of boss fights; it's no wonder I've been playing it in all my free time. Cuphead's story line starts with you in trouble with the devil, and you have to pay him back (basically doing all of his dirty work). As you progress in the game you unlock really cool ultimate abilities that help you fight the bosses, and at some point, the devil himself.
Currently I am playing it on the Nintendo Switch, (even though I just found out it's also on the Ps4) I really like the handheld version of it. It keeps it feeling almost like it's a throwback vintage game from your childhood, only much better graphics.
If you're looking for a fun game, that makes you a little sweaty, but you'll actually enjoy.. I recommend Cuphead.