Omfg Streets of Rage 4 is so god damn good. I love me some side-scrolling beat 'em ups" (3D Streets of Rage 2 on the 3DS was my goto bathroom break game at work for awhile) but it can be a hostile genre. Arcade beat 'em ups are cheap and frustrating to steal your quarters, and even console ones made you play the whole game in one go so they're still repetitive.
But Streets of Rage 4 chucks all those issues out the window by saving what levels you've completed but keeping difficulty and replay value by making your and the enemies' move sets complex enough to be fun to learn without making it so complex it ceases to be mindless curb stomping fun. It's the perfect beat 'em up.
And Blaze's boob jiggle is the real deal.