I definitely went in with low expectations and was happy to have them exceeded at least. The worst bits were the Illumination tropes of course from the pop songs* to the staid and overused jokes but those were thankfully restrained compared to their other movies. Otherwise it was pretty fun, would have liked some of the worst bits cut off and used to give a bit more background/arc to Toad and Peach, hoping that they lean into the good parts of the movie for future sequels and not the obnoxious parts but we'll see. Some more detailed bits (probably more negative/nitpicky) under the spoilers:
One of the problems with movies based off an IP, whether it's a comic book super hero movie or a cartoon/video game IP, is that they have to lampshade anything that is overtly too 'comic book' or 'video game' which always comes off as if they have no confidence in the movie they're making and takes me right out of the film. In extreme cases this is how we get things like live action hybrid films like Sonic or Smurfs. The movie wasn't devoid of that kind of thing, but mostly just let the film be a Mario adventure, even in some places leaning in heavily to the 'rules' such as how power ups work. I loved this, but it had the unfortunate consequence that whenever they did lambast themselves, or make a joke that felt too out of place with the world, it was a full record skip that took me out of the movie, even when I knew they were coming like the suicide ideating Luma. I hate that shit in other Illumination and lesser 3D kids movies, but at least it's usually consistent with the rest of the film. Here it's just very distruptive and tonally jarring.
Speaking of tonally jarring, the Luma was my second most hated bit of the movie; Worst than that, and I checked with my partner and this rubbed her the wrong way too, was the Wedding/'ritualistic sacrifice' sequence. Now Bowser's usually a bad dude and I'm glad they were willing to go dark in this movie, but that was out of left field, overly morbid and barely made any sense - what purpose does it serve Bowser to murder these people? Why make it a weird wedding gift? I don't want to steal too many words from my partner's mouth, but I agree that it just felt like a lazy set up for the next action break (she also had an awesome idea that ties into early Mario lore where the prisoners could be turned into blocks or statues or some such to build some kind of structure, something that could still have kept the stakes of the scene, created a fun setpiece for that part of the film and could still be dark without being so off-tone)
Characterizations were good, I can't believe we got to see Mario's whole family (Charles Martinet is Mario's dad, so he got more than just a real bit cameo!), I wish there were more Charlie Day Luigi but he was perfect. DK & Mario's rivalry was fun. Bowser was great, also glad they let Jack Black do his thing, honestly reminded me a lot of Bowser from the Super Show cartoon except more fun. Honestly a lot of the film reminded me of a 'good' version of the cartoons, so I think the commercial at the beginning was less a reference and more of a mission statement. This includes Toad and Peach, for better and for worse. For Toad, I really want more background on that character - where was he going when he runs into Mario? Was he always going to the palace? Was it his dream to be the Princess' retainer or guard or whatever and this Mario guy just showed up? Was he trying to prove himself to the other toads? When I say I want more background on these characters I don't mean they need a full arc or a dramatic backstory or whatever. Hell, make it a one off joke, as long as the characters have a stated intent so that their scenes land more! I have similar feelings with Peach but I know that's a landmine that other people are better suited to speak to than me, so I'll just say I enjoyed the character and Anya Taylor-Joy was suberb, I just wanted more. Not much more; even 2 - 5 minutes more time with these characters would have improved this movie immensely, and there's definietly enough slow motion shots of Mario saying 'Mama Mia' or whatever and a very unnessecary Luma they could have cut to gotten those into the movie.
I guess to summarize, the parts that were a Mario movie were good and that was thankfully most of it. Oh and the movie looked gorgeous and the soundtrack that wasn't licensed was extremely good, as was how the movie was directed around the score. Some parts were almost like a musical, perfectly suited for a Mario movie.
* There was one pop song bit that I did enjoy, the 'No Sleep 'Til Brooklyn' sidescrolling scene. Perfection, no real notes there.