you need the doom wad files to run the psp doom port..
demo of which is here:http://www.tucows.com/preview/205619
if you want the full game or doom 2 youll have to get the full wad files,. which can be taken from any full copy of doom, or possibly ps1, or mb xbox versions.
though best route is to buy the collectors edition id say its a pretty cool deal.
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