I think I'd be fine with it if they hadn't said the boss was an equivalent of a Lvl 5. He's only about 1/3 of the way through level 2, that's just stupid that the Author went with his ability allows him to punch up that far. Even without the sword, he came close to inflicting a deadly wound the first time.
Still, this was a better version of the fight than the anime. I really didn't like that version.