Bayonetta was a good game, but could be very tough in spots. Since even on normal the enemies do a ton of damage (so even though Bayonetta's health gauge looks pretty big, it vanishes in only a few hits). Boss fights were especially bad since they often had 2-4 health bars and took a ton of damage.
So you really need to learn to use the Dodge button. (Since dodging at the right time activates Bayonetta's Witch Time so things move slower and she does more damage.)