The trick to beating it easily for me is to just stand right up against the shield (the shield doesn't do contact damage) and then when it goes to swing, jump and hit it in the head. It kinda seems like you will get hit but if you time it right it will miss. Also one small tip for anyone struggling with the platforming, the game really wants you to just kinda hold forward and keep going, instead of trying to stop on a small platform, just jump as soon as you land on it instead and you won't have to deal with sliding.