Sony has promised a number of "very unique" game titles for the PlayStation Portable (PSP) later this year.

Outside of Final Fantasy: Crisis Core, Secret Agent Clank, and a line-up of additional sports games, Sony marketing manager John Koller said he didn't want to "scoop" anything, but that some "very unique" titles are coming later this year, with a focus on "franchise umbrellas".

In terms of downloadable games, Koller said consumer education will be a hurdle in the coming months because the PSP store is still in its infancy. "The Store will be very, very important for Sony and for the PSP's future," he said, including both PS1 and PS2 re-releases.

See all game reviews

Koller also mentioned that upcoming PSP peripherals will include a keyboard (for internet browsing), camera and North American version of the GPS add-on planned for release this autumn.

To date, Sony has sold more than 31 million PSP systems worldwide. By comparison, Nintendo has sold more than 65 million global DS units.

See Business Advisor for the latest technology news, reviews and tutorials, plus the chance to win a Dell laptop