If you're making a portable you probably need something to watch it on. (Unless you want to guess what's happening in the game, but I wouldn't advise that) Anyway, this forum is your "Hacking a pocket TV/screen" one-stop solution. Share your experiences and knowledge here.
Are there any rubber pads anywhere? If so, pry them out and there might be a screw underneath, hiding like a little rat.
Look under any stickers.. That's one of the little tricks companys like to use to hide screws.
On the insides there are most likely some snaps, try prying it apart with a flathead screwdrvier, but very careully, you don't want to snap something off.