Bleach OVA: The Sealed Sword Frenzy is just a silly 32 minute special where a guy named Baishin undoes his seal and needs to be either killed or resealed.
Something about which nobody can write a review with 2200+ words without spoiling but it came to this point.

While it can be considered an extended filler episode, it has its merits like the humor. Despite being portrayed as something very serious, the silliness that was missing in Bleach after the first arc can be seen such as using the lack of understanding of Renji and Rukia about the living world and how Ichigo or others react to it.

A lot of characters are involved mainly just because. Unlike in the movies, there is no massive Bankai spam. In total only three Bankais released but only two of them mattered for the story.

The fight against Baishin is entertaining somewhat, certainly more than most Bleach movie fights.

Criticism is that some characters have some plot induced stupidity by not doing the obvious. There is also a massive inconsistency in power jumps like between Ichigo's Shikai to his Bankai compared to other characters. Especially since he suppose to get weaker as the story goes on and Baishin stronger. Really illogical but what can be done.

Also the fact there is another enemy that can summon hollows for some reason especially when there is no hint justifying for such ability to exist. Also there is a scene where Rukia in her Shinigami form tries to lead human to safety despite being invisible to them.
Finally Baishin's implied motivation why he does what he does makes no sense as we cannot sympathise why he wants what he wants.

The cast is great as ever like Ichigo's family reacting to something. Rukia being bea (is what I would say if I were a Rukia simp which I am not... what are you looking at me like that? Seriously). Well, Rukia is really portrayed as stupid but adapting to the living world and seeing her react to what seems mundane to us mortals is still a fun sight.
Orihime being in the background where she belongs and doesn't annoy anyone. Urahara giving exposition. And much much more.
As usual Ichigo is the only one who pays attention to anything and is the voice of reason in this entire mess. He understands who Baishin is. He asks the important questions. Is made fun of for his lack of basic experience as a Shinigami because he is just a substitute Shinigami.

If you like early Bleach humor like how Kon gets abused and whatnot, it is definitively worth a watch. Otherwise don't expect too much. The concept of what Baishin is is also interesting and hasn't been done in Bleach before or after.