Actually its whats called a Light Novel, the manga adaptation only coming next year according to wiki. The basic plot summaries do seem to match up - man enlists in the Earth Defence Force or whatever, fights aliens called Mimics, gets stuck in time loop, abuses the system to raise his skills whilst trying to find a way out of his fate.
Now unfortunately as I don't know much else about the source material beyond that, I can't really tell you based on the trailer how well this film is doing as an adaptation. D-Day with power armour might be part of it, might not be. Its not the first time the groundhog day loop has been put to use like this, but still it does interest me a little. Hell, the fact they went for a light novel and actually got something about it this far into production is kinda strange, given all the hype about supposed adaptations of stuff like Akira or Death Note which end up in perpetual limbo.