While I don't mind either the joke incantations or the credits page, please don't use real phrases for them, 'cause it gets mixed up with the regular text. I had to stop and reread page 17 because at first I thought the incantation was part of what she was saying.
As for the memier translations such as page 20, it's not like it doesn't convey the meaning but it does come off as a bit jarring. And page 29 definitely didn't make sense.
Wrt the last panel of page 30 ("she had good power but it's useless"), I'm not sure of the intended meaning. Something like "She's decently powerful but lacks skill"?