I started to watch this anime, because I'm a big Hayashibara Megumi fan, and I decided that I will watch every animes, where her voice is audible, even the smallers ones.
The Muteki-Ou! Tri-Zenon belongs to these "smaller" animes, and to those, which are her greatest works.
The biggest mistake of this anime is the characters are too simple, I couldn't believe of them that they are heros, who are ready to save the world. Especially Kanna, who's a "cry-baby" girl, she always shouts in her fear when a battle starts, or she needs to attack. Hayashibara Megumi gave her voice to this girl, and this character
totally not suitable to her voice, even it was sometimes annoying.
Because the character's personality were too simple it made the complete story insignificant, I wasn't interested in what's happenning to them. There were some interesting and funny moments, but the battles were totally uninteresting.
It was interesting to watch this anime as a Hayashibara Megumi fan, otherwise I don't offer it, it's not hard to find a better one.
But the opening and the ending are great songs.