A rather easy boss. He is only dangerous after walking (you are NOT safe on the platform on each side - use them to jump over him before he reaches you). He waits for a few seconds and repeatetly punches the floor while following you.
Hit him as much as possible while he stands still and try to get a few hits while he walks around. He shoots a few fireballs from time to time but they do only 1 damage and can be ignored.