(Review originally written at 20 April 2010)
You have to simply take this type of movies for what they are. It's quite hard to say anything serious about them because they are all looking very outdated, features some bad acting and of course also don't have the most clever or original scripts.
What makes this movie very fun and watchable is the fact that it's almost non-stop movie monster action. Halve of the time during this movie you're watching a bunch of guys in suits walking around at a set with miniatures but it's all simply fun and good to watch. Lots of things get destroyed and the army is basically using everything it got to stop the two Gargantuas from reaching Tokyo. At the same time the two Gargantuas 'brothers' are also battling each other, so we have some action coming from basically every angle here.
It means that the 'human' story of the movie gets sort of pushed to the background but this is not necessarily a bad thing. It only means that the movie decided to go for entertainment rather than depth. Also not a bad movie, considering that the acting in this movie isn't exactly the best. Russ Tamblyn's overacting is quite laughable.
The movie is not necessarily a sequel to "Furankenshutain tai chitei kaijû Baragon", since this one doesn't even feature any of the original characters from that movie. It means that you don't necessarily need to see the first movie before watching and enjoying this one. The movie is from the same director and pretty much features the same crew as well, who did lots of movies like this together. Honda is also the director of the first original "Gojira" movie.
This movie is simply good and entertaining for what it is.