This is one of those shows that needs to be opened up with a certain disclaimer before I review it. In the case of SSSS. Gridman, I did not know this going in but it is part of a larger franchise, one that is oddly not an Anime. As far as I can tell, this and some short the director also made are the only anime related pieces of the franchise, the rest being a live-action show, Gridman the Hyper Agent. So I go into this having had no knowledge of the franchise at large.
That out of the way, Gridman stars a boy named Yuta who has lost his memory, He seems to have some connection with this being called Gridman, and by using Yutas body and a certain computer, Gridman can manifest into the world to fight Kaiju (Giant Monsters). The twist here is that after each day, all damage from the battles is restored and anyone killed by the Kaiju during the night disappears from the world, with everyone having new memories of how that person died sometime in the past.
Yuta and Gridman, despite having no memories of who they are, don't have their memories of the previous days reset like everyone else, they remember the Kaiju and the people who disappear. This extends to a few other people as well, specifically Yuta's friends Sho and Rikka. For some reason exposure to Junk, the computer, and Gridman seem to have an effect on the reset each passing day. There is also a group of people capable of turning into upgrades for Gridman, though not all can be active at once.
The thing that first strikes me about the show is the fights. The show I am most reminded of when watching is G Gundam. It sounds like an odd comparison, but with how Gridman looks like a Mech, but fights like a Martial Artist and calls out all kinds of attack names, it's kind of got that same glorious cheese factor G Gundam had. It doesn't reach the heights of Tequila Gundam sadly, but it's great all the same. Every fight in this show is high impact and thrilling and serves as the main reason to watch it.
The characters are all pretty decent as well, though to be honest the only one that stands out is the character who serves as the show's antagonist for the most part. I won't spoil it, but when you start to realize there role in this world and the reason behind their actions, it becomes incredibly hard to hate them. Yeah, you don't support their actions, of course, they are never painted as being morally justified, but all the same, the villain remains incredibly sympathetic.
The story itself though kind of struggles to remain interesting in most other aspects though. There is one thing that works against this series, and that is going in without the knowledge of the rest of the franchise. While the story is largely self-contained, there are a lot of elements that go unexplained or that you just kind of have to accept.
A slight spoiler to explain my point, but there comes a point you learn not all Kaiju come from the antagonist of the series, and there is a Kaiju who explains to the main character a lot of secrets about how the world works. This Kaiju helps him out because apparently, Gridman helped out this Kaiju's 'Mother' in the past. You never find out what happens, and with the final twists of the show revealed you are left wondering how this particular Kaiju ever ended up here in the first place, and end up not really knowing how this world even works as a result. It feels like you are missing a lot of information, and when looking into the rest of the franchise I kind of walk away understanding a little more, but still not that much since I only read a few brief descriptions.
Despite a fairly weak narrative and cast, the show is still pretty funny. There are a ton of jokes that hit their mark, and character interactions are all pretty solid. The cast may not be particularly great, but there aren't really any bad characters either.
The fights really are the main draw of the show. The great animation, the over the top moves, and the cheesiness of the whole affair do a lot to make up for the weaker points of the plot, and even that is made worth it by the well-done antagonist of the show. SSSS. Gridman is definitely a show worth checking out if you're up for a fun action show, with just enough quality writing to make it more than just spectacle.