Sadly, only the grating English dub has a remixed 5.1 track to go along with it. The Japanese mix is Dolby 2.0 mono. Regardless of your choice, this is entirely front loaded, with strained highs and clear dialogue. Sadao Bekku’s sparse soundtrack is occasionally lost in the mix, or too distorted to make out. Fidelity is better with the original language, although it’s a close call either way. 
The Tokyo Shock label has always come through for these Toho efforts, and this is no different. Akira Kubo provides a commentary, which while not that technical, does tell some stories from the set. An interview with Teruyoshi Nakano is almost 30 minutes, delivering behind-the-scenes photos and details on the effects (and making up for the lack of technical aspects in the commentary).
Spoken Word from Masami Fukushima is a short story read by the writer of the film. A selection of trailers, including one for Mantango, are all that remain. 
Mantango was released in the US direct to TV, dropping the “Mantango” name and sticking with the simple title Attack of the Mushroom People. It’s not hard to see why the film would be a tough fit in a country still being flooded with giant monsters and cheapies coming out of the ‘50s.
Article comments
1 - Luigi Bastardo
Ah, such a great movie! I need to re-watch it again one of these days.