Before the start of this review, it has to be said that the number of chapters this manga exceeds that of the ones MAL listed. The actual amount of chapters is 57.

Kinnikuman Nisei: All Choujin Daishingeki is a spin off manga of Kinnikuman Nisei aka. Ultimate Muscle which is a sequel to Kinnikuman. It is an alternative version on how events of Kinnikuman Nisei play out with the main lead Mantaro Kinniku, the son of the protagonist of Kinnikuman, coming to earth to fight Evil Chojin as a Justice Chojin. Chojin are basically Supermen.

There are differences to the original Kinnikuman Nisei like Mantaro's backstory being altered and a few characters having access to moves they worked for in the original story immediately. Also story arcs are much shorter than the original with less pages per chapter which makes it a much quicker read compared to the original.
Many beloved characters are far less interesting personality and origin wise not to mention lack some good fights. Some characters are allies out of nowhere and you just have to accept they were part of the main and support cast the whole like like Rinko (or Roxanne in the English version). Also for most the story the fights are less brutal, only in the final arc the amount of brutality starts to increase.

While these things make All Choujin Daishingeki inferior, it still has some really well done elements. Some characters get replaced by other characters like instead of fighting Ricardo in the Ikemon Chojin Olympics, Mantaro is fighting Munta instead. While she has a questionable designs and acts like a comic relief obscure character, there is more to her that meets the eyes. Speaking of female characters, the story also has some female Chojin representation that put an impressive performance.
Another positive is that Gazelleman (or Dik Dik Van Dik) actually has on page wins while in the original story he didn't win a single fight since his debut.
Even despite being inferior to the main series, it still has fights Kinnikuman is known for. Characters have various designs since they were sent by fans with minor edits, and the authors make sure that each of them at some point in the manga get credited. What makes it even greater is that said character designs play a role in combat with each fighter coming with unique sets of strength and weaknesses. For instance, Checkmate is a Chess themed Chojin who can transform into Chess based characters and gain abilities based on what he chooses. His default humanoid form is the king. When he turns into a tower, he becomes as durable as a tower. As a knight, which looks like a horse as a chess piece, he can move faster and is as heavy as a horse which plays a role when he uses his signature technique to crush his opponents under him. Or Bath the Shower, a Chojin exclusive to this manga so far, is a bathtub chojin and can freeze you with his cold shower or lure you into a trap with a hot bath. Some elements some people feel when they take a cold shower are also incorporated into his moveset like him being able to turn the water that comes out into ice.
Even the ring they are fighting plays a role as characters would use the ring ropes as part of their attacks or even the iron pole. Sometimes they fight on a different ring for instance the canvas is replaced by an actual trampoline which gives some techniques an advantage and others a disadvantage.
Meaning like in all Kinnikuman stories, there is a lot of strategy involved in fights using ones abilities, strength and weaknesses as well as the environment to their advantage.

If you are a Kinnikuman fan, it is still worth checking it out. If you haven't read Kinnikuman or Kinnikuman Nisei and are conflicted whether you should or shouldn't, you can read All Choujin Daishingeki to see if the setting and fights are your fancy above a good story with deep character arcs. Because if you enjoy what you see but want something more, you will definitively enjoy the parent story.
In other words, it is worth checking out.