Story: After the initial events of EDF 2017, the remaining Ravagers have been wiped out. Humanity has begun rebuilding their world. Ironically, it is the technology obtained from the Ravagers that is proving to be a boon in this rebuilding process.
On June 28th, 2025, 8 years after initial contact, disaster strikes. Surviving Ravagers have burrowed deep into the earth where they have been waiting… And multiplying… Now the EDF must stand up again, aided with new technology, to battle th- ah, who cares. It's marines versus space bugs. Screw the plot!
As for added features, EDF4 will include online play (the exact number of possible simultaneous players has not been announced), as well as new weapons and enemies. D3 has also hinted that enemies will actually eat people this time around, although details on that feature have yet to be announced.
In the meantime, famed Japanese B movie director, Minoru Kawasaki will be releasing his live-action EDF commercial on September 26th, one day before the release of Earth Defense Force 3: Portable for the PS Vita.
Earth Defense Force 4 is scheduled for release in Japan in 2013 for the PS3 and Xbox 360.