The Game Boy Advance SP is backwards compatible with Game Boy and Game Boy Color games, which means you can insert your Pokémon Red cartridge and play it on the GBA SP. However, please note that the Game Boy Advance SP does not have a color screen, so the graphics in Pokémon Red will be in grayscale instead of the original colors. Additionally, some features that were available on the original Game Boy, such as the rumble feature, may not be supported on the GBA SP.