The music is 3.5 stars for me. "I always wanted a brother" is easily the best song in the movie! Very much like "I just can't wait to be king" but able to stand on its own. The rest of the songs are kinda meh. They just can't live up to the original 1994 soundtrack.
The story is very good, however, there's inconsistencies and plot holes that don't fit into the 1994 version (and some holes that don't fit well into the 2019 remake either). The story gets a 4 star rating from me as a stand-alone story for Mufasa but not when you tie it to the other film(s).
The visuals are stunning! The facial expressions are amazing! 5 stars for visuals.
The inconsistencies and gripes I have are:
Scar decides to betray Mufasa over a crush on Sarabi. Seriously? Incel Scar? Not a fan of that.
Mufasa has no royal blood. In the original film, he tells Simba about the great kings of the past. It doesn't make sense that there is no basis or mention of these great kings that are supposed to be in his lineage if he's simply an orphan and an outsider taken in by a very lazy king Obasi (who never wanted him in the first place). Also, Mufasa says his own father told him this. Obasi surely didn't, so it must have been Masego (his biological father), but if Masego is not a king, and only appears with his mate Afia, where is the rest of the pride? Are they just wanderers? The "great kings of the past" need to tie into Mufasa's story better.
Zazu tells Simba and Nala that they are betrothed and that it is a "tradition going back many generations". I guess this could work on Sarabi's side, as he is her scout and she is a princess, but it makes more sense if he was always Mufasa's majordomo, not Sarabi's scout or protector.
In the 2019 remake, Zazu tells Mufasa to go easy on Simba and reminds Mufasa that he remembers when Mufasa was a certain headstrong cub who was always getting into scrapes. In Mufasa: The Lion King, Zazu meets Mufasa when Mufasa is a young/sub-adult or older adolescent male lion and not a cub, so this a major inconsistency.
It is also mentioned in both the 1994 film and the 2019 film that "Simba is the rightful king". ....How? Mufasa never had any royal blood in his story, but Scar/Taka did, so Scar is really the rightfully king.
There's too many inconsistencies to fit the movie into the previous films, so I see it as a stand-alone movie and an alternate timeline to the others.
Disney and its writers/directors need to pay more attention to these details as they are important and crucial pieces to the bigger picture.
But overall, I really like the movie. Taka/Scar is given more depth to his character, and subtle details that he would eventually turn evil, although I did find it overdramatic that he would turn on his brother over a girl. I suppose the impulsive act from his jealousy was just that: and impulse decision that he did later regret, but it was still a bit jarring for him to flip the switch from being so loyal and caring of Mufasa to suddenly sending the wicked and sadistic Kiros on him so readily.
The overall score I give Mufasa is a 4 out of 5 stars for the sole-standing but well-written story, a decent soundtrack, and stunning visuals; the film lost a star for its inconsistencies and failing to tie itself to the previous film(s) in an accurate way.