Summary: >
This title begins with some cast members from Nadesico (another anime entirely), going to a theater to watch none other than Gekiganger III. While technically Gekiganger was nothing more than a show within Nadesico, this is about all they really have in common so the tie-in stops there.
Long ago, the people from the neo-paleolithic era left a blueprint for a giant robot - Gekiganger III (what happened to 1 & 2? Who knows). From there the show (even the music) goes on in a blatant in your face parody of many mecha anime. The story is more like a collection from the fictional Gekiganger III series, so there's not much of a story to really describe...
Thoughts: >
Gekiganger III is a parody of mecha anime, however you need to keep in mind that there are two avenues of seeing this title, which can affect your opinions of it. You can watch it having already seen Marital Successor Nadesico, or watch it having not seen that series. Gekiganger III is the anime that the Nadesico character Akito is obsessed with. If you've seen Nadesico, then you've seen excerpts of what Gekiganger entails - much of which is covered in this title again. I watched Gekiganger 3 before I saw Nadesico so I have a weird sort hindsight about this title.
As a parody this title goes full tilt into the same avenues that old giant robot anime series from the 70s used to do. Now being a fan of mecha anime isn't necessarily enough in order to "get" Gekiganger III, since newer mecha anime is very different from the giant robot anime of old. As such having at least a passing understanding/interest in series such as Voltron is probably required, although just understanding where those series were coming from is probably enough.
And you also must keep in mind that Gekiganger is a parody, not an all out comedy. As such the humor is supposed to come from this anime poking fun at itself, not from actual jokes of any sort. Again that's why it's critical for knowledge in old school anime if you've never seen Nadesico. Having seen Nadesico, you should know EXACTLY what you're getting into, and whether this is something you'd want to watch. If you also got the fact that Nadesico is on some level also a parody, then this would probably be a must watch title as well.
Anyway, I would highly recommend this to old mecha anime fans, or some people who just want to watch an anime which is a downright silly parody. It's just a lot of fun. Also entailed are a few teasers from the Nadesico cast in the beginning and end.