So I've been working my way through the game the past few weeks and I've finally finished the main storyline, very pleased with the game overall and it has completed validated owning a PSP. 
 
With that I have now moved on to the Extra ops, more specifically the upgraded AI battles. I attempted the Pupa II stage and although I beat it I can tell most of these are going to be a huge pain solo. It looks like this forum isn't very active but I thought it'd be worth seeing if there is anybody around that wants to attempt some co-op? 
 
I just need to figure out how to get AD Hoc working and check back here. I need to use my Stealth Gun and Tank Box!