Very good news for anyone wondering when Earth Defense Force 2017 Portable would be arriving in North America: it's out in just a few weeks, on January 8th.
The bad news: it's download-only, and it will cost $40 (or, technically, $39.99). And unlike New Little King's Story, which was PSN-only in North America but got a physical release in Europe, you won't be able to import a physical copy from across the Atlantic, as it's getting the digital-only treatment over there as well, albeit one week later. (However, if you're really, really set on avoiding the download route, however, and you don't mind not understanding a word, note that the EDF 2017 Portable did go the cartridge route over in Japan.)
Still, if you can swallow the price, it's sure to be a worthwhile endeavour. It will have online co-op and versus multiplayer, and the game's servers will allow North Americans and Europeans to play against or alongside each other. Plus: giant bugs and 230 different weapons seems like it should be a fun, explode-y combination.