To get what I liked out of the way, the suit designs and special effects were really good for the most part. Black Sun easily has some of the highest quality suits in the Kamen Rider franchise. The fights are really well choreographed and have a very visceral feeling about them. The actors all also do a good job with their roles.
However, the plot for Black Sun is full of holes and not very well thought out. The problem with it should be obvious, the series tries to a racism allegory using mutant monsters who need to drink a serum made from dead humans in order to continue living. Taking the transhuman Nazi monsters of the original Kamen Rider and flipping them to be a superpowered oppressed underclass creates a number of issues, namely in that the show tries to explore the realistic ramifications of the world it portrays whilst also forcing it to parallel the civil rights movement. This leads to things like our hero Kotaro and the over-the-top racist anti-kaijin human character having similar goals of wanting to see kaijins eradicated, just by different means (Kotaro wants to prevent any future kaijins from being made, while the human racist wants to kill them all). While Kotaro's actions are perfectly justified in universe, since kaijins began as humans who were forcibly experimented on, it doesn't jive with the civil rights analogy the show portrays.
If the show kept itself divorced from the real world and had a plotline with its own self-contained politics this wouldn't be as a big an issue, but the various explicit parallels to real-life events and movements strewn throughout only serve to mask the fact that this show has no real consistent theme or message on the issues it purports to critique.
However, the plot for Black Sun is full of holes and not very well thought out. The problem with it should be obvious, the series tries to a racism allegory using mutant monsters who need to drink a serum made from dead humans in order to continue living. Taking the transhuman Nazi monsters of the original Kamen Rider and flipping them to be a superpowered oppressed underclass creates a number of issues, namely in that the show tries to explore the realistic ramifications of the world it portrays whilst also forcing it to parallel the civil rights movement. This leads to things like our hero Kotaro and the over-the-top racist anti-kaijin human character having similar goals of wanting to see kaijins eradicated, just by different means (Kotaro wants to prevent any future kaijins from being made, while the human racist wants to kill them all). While Kotaro's actions are perfectly justified in universe, since kaijins began as humans who were forcibly experimented on, it doesn't jive with the civil rights analogy the show portrays.
If the show kept itself divorced from the real world and had a plotline with its own self-contained politics this wouldn't be as a big an issue, but the various explicit parallels to real-life events and movements strewn throughout only serve to mask the fact that this show has no real consistent theme or message on the issues it purports to critique.