You see this in pretty much any 3D made PSP game, or port of a PS2 game. Tekken had quite a bit of seams, Tony Hawk Underground 2 had that and various 3D models going through others, the Metal Gear games had this problem, and pretty much every 3D game besides Playstation ports and a few others didn't have this (Mega Man: Powered Up). Is there something with the development kits, or the hardware itself that causes it, or is it just a byproduct of importing a model over to the PSP format (Tekken, Metal Gear), or just something the developers cut corners on in order for it to run at a reasonable framerate?
i think all the games for the psp are rushed. ANd they are all very simple ports of games that were going to be put on ps2 but didn't get the budget.