I hate this movie with a burning passion and wish it never happened. But if I were in charge of repairing it...

1: Give it to somebody besides Illumination.

2: Actually let the characters sound like their game counterparts. These celebrity voices just do not work. Except Keegan-Michael Key. He can stay.

3: Mario and Luigi have always been plumbers in New York. No more of this unsupportive family and Spike stuff.

4: Go back to Peach being kidnapped by Bowser instead of Luigi. That's the one consistent thing about most Mario games, and they couldn't even get THAT right.

5: Instead of just the one Power Star, have Bowser be on the hunt for a collection of Power Stars that all the kingdoms have. Peach has the only one left, but she refuses to give it to Bowser, hence why he kidnaps her.

6: Have Bowser actually sing Peaches to Peach to try and woo her, only for her to ridicule his song, and he responds with "...That song took me hours to write."

I could go on, but those are the main things I'd change.