Earth Defense Force 2 Portable is, predictably, a port of the original Earth Defense Force 2 for PS2. In addition to the 71 missions included in the original, the PSP version will boast brand new missions. According to a translation by Andriasang, all missions can be played with at least one friend over local wi-fi, as seen in the picture above. However, D3 hasn't confirmed if co-op can support any additional players. (We all know four is the magic number, right?)
EDF2P is currently scheduled for a Spring release next year. Considering Earth Defense Force will be making an appearance in the US on PS3 and Xbox 360, it seems possible that this handheld game will be localized as well.