The old movie with Bob Hoskins (showing my age) was overall a better, more accurate to the game, and well written movie than this one and that's saying something.
It's not as bad a 1-star, but all those reviews hit the nails on the head. Poor casting choices, poor writing, and far too minion-esque, all hidden behind pretty animation which seems to be the nature of films (and games) of the last decade. Hide lazy, low quality stories behind a facade of high quality animation / CGI.
Pixels and Ready Player One, for instance, manage 80's gaming nostalgia that those of us of a certain age enjoy, but keeping it (mostly) kid friendly and enjoyable. Mario seems to have been written by the worst kind of incel who placed himself as Koopa, with Peach becoming his perfect Waifu and it's stomach churning to watch. The only redeeming point is kids will be so distracted by the graphics that they won't notice. I almost vomited for the Koopa song, bleurgh!!