Direct from the source - the official playstation site: http://uk.playstation.com/games-medi...e-best-of-PSP/

and in case you don't wanna click the link, here's the quote:

Only the best-selling games qualify for Platinum status, so you know that when you buy Platinum, you’re picking up a PSP favourite. The perfect way to show the brighter screen of PSP-3000 in its best light, or for filling a gap in your collection, there’s something for everyone on Platinum.
... and yeah Alex, I see the point you are making, but - it aint gonna be anytime soon, which is the point I was making. Eventually, we'll get a PS4 too but ya know what - speculation is speculation, it aint a fact til it's confirmed...

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