I was sure at first this would be a fan made trailer or something, but dang if fans can make this...
It looks easily 40 times more badass as a trailer than even Toho's new Godzilla Resurgence (http://grogheads.com/forums/index.php?topic=16741.0). Structurally it seems to be set up as a sequel, or quasi-sequel (kind of like
Gamera: Little Brave One a few years ago), to the apocalyptic end of the acclaimed 90s Gamera trilogy. This can only be a good thing. If the movie is real.
But even if it isn't, awesome props to whoever made that.
Alas -- the video released back in 2015, shown above, which leaves out some footage of another monster in other versions, was not a trailer for a new film or even a proof-of-concept trailer. It was only a short film, or part of a short film, celebrating the 50th (?) anniversary of Gamera's creation.
Sadness. Whoever owns the rights might of course go for a new film based on fan response, but who knows.