Who can help explain what the handheld game machine really looks like?

The difference lies in the game screen. I also read a lot of comments before buying. I think nds is similar to psp. It was discovered only after the two machines were actually started. There's nothing like it Nds recommends Pokemon series, and other game screens can't stand it. Psp recommends monster hunter (I played for more than 3000 hours), dream star (which can also reach thousands of hours) and battlefield Valkyria.