Well the 'bad' news is that this is going to be a negative review as I despised this film. The 'good' news is that I appear to be a in distinct minority in this matter, since most reviews - including that of my son - are very positive.
So why did I dislike it so much? Well firstly there is way too much time spent on non-central characters. We don't see the main protagonist Miles Morales actually do anything until almost thirty minutes into the film! Lots of other characters are thrown in almost from start to finish. I get that in a multiverse storyline this is going to happen but my problem is that so many of these characters appeared to me as shallow, annoying and unnecessary.
The artwork was, at times, really off-putting for me, too. It served a purpose: different worlds in the multiverse had different art styles and some of them, such as Miles', were fantastic. Others however, most notably Spider-Gwen (though annoyingly she is known as "Spider-Woman" in the film) had an impressionist style of artwork that I didn't feel worked well in the context. I know her own comic is drawn in the same way so I get the logic behind it, but it just hurt my eyes and confused my pupils on the big screen. And speaking of Spider-Woman Jessica Drew, as a child, I had a crush on her so I felt let down when she didn't make an appearance anywhere here though perhaps she'll appear in part 2. What we do get is a pregnant Spider-Woman racing around and jumping everywhere, an obese Spider-Woman and a T-Rex Spider-Man, seriously.
The main sticking point for me, however, was the dialogue. The previous Spider-Verse film had a good balance of a young, interesting character for the new generation of comic and hero fans and humor and dialogue for the parents in the audience. This film tips the scales and is rammed full of lazy, shallow, tedious wisecracks that serve no purpose but to make the characters all similar in how unpleasant they are. Again, don't get me wrong, I know well that humour and wisecracking has always been part of the Spider-Man identity but I have always felt Peter Parker used it almost as a defence mechanism for his own nerves and insecurity. Now it's just an obnoxious substitute for meaningful dialogue. The only really deep conversations always revolve around Miles and as I mentioned, he spends a lot of time in the background in parts of the film.
Speaking of Peter Parker, he's now an overweight, bungling parent who gets criticised by his peers. By pure coincidence he's also the only straight white male in the film.
There are some good aspects. The movie ends on a good cliffhanger with a good twist, however it does feel like this instalment was stretched out and bloated to make one storyline fit two movies. Some of the insider jokes and references to other Spider-Man media were enjoyable and when it wasn't burning my eyes, the animation and artwork were fantastic.
So yeh, I wasn't keen. A lot of potential wasted by arrogance and lazy scripting in my view but speak to most other viewers and you will get a very different take.