This is simply a compilation video of multiple episodes from the super robot show "Genki Bakuhatsu Ganbaruger" like you'd find it on old pack-in VHS tapes, sold together with toys in pre-internet days.
Aside from the professionally done voice acting (the only characters appearing with new dialogue are the three heroes Kotarou, Rikiya and Yousuke), pretty much everything else is recycled scenes from the show.
Being a super robot show, the characters talk a bit about their superpowers, robots, enemies etc. while reused footage plays. And thats it for content. There might be some interesting trivia now on then, but people looking for that are better advised
to check the “Eldran series” memorial book on Genki Bakuhatsu Ganbaruger. In general, it sadly doesn’t diversify itself from most other compilation episodes. It’s plain and simple boring most of the time.
Ganbaruger: Hyakka was included in the recent bluray release of Genki Bakuhatsu Ganbaruger, but unlike the regular episodes, it wasn't remastered.
This is an acceptable single time watch for fans of the series to hear the charismatic characters talking new lines, but nothing to go actively searching for. As an unintroduced viewer, by all means, watch the base series instead of this, which is a true hidden gem.