Aside from a second analog stick, the PSP is missing the second set of trigger buttons found on all PlayStation controllers. If you're utilizing remote play with a PS3, you can map PlayStation One titles' L2 and R2 functions to the analog nub. However, someone thought that was rubbish and created their own L2/R2 modification to the PSP. You can do it just like the modder "Electro", assuming you've got access and are fairly talented with a soldering iron. It doesn't look that great, but if it works, you'll have the last laugh.