This didn't do a lot for me. It works well enough as a portable title and it laid the groundwork for the mechanically impressive MGSV, but it's not super fun to go back to by itself as a proper entry into the MGS series. Definitely works better when you consider the platform it was originally made for but if you don't have a PSP then you're stuck in your living room with these incredibly watered down systems.
Still, a fun take on the classic MGS formula and a nice little PSP game. It's a shame that playing this is basically mandatory to be up to speed with Ground Zeroes and by extension MGSV.