Whereas all of the other video game versions of Eragon put you in the shoes of the titular hero, the PSP version puts you in the role of Saphira, Eragon's scaly blue dragon companion. (gamespot.com)
That link forms the basis of combat, with you able to direct your dragon companion towards enemies, either backing you up in a fight or taking out other threats on his own. (thesixthaxis.com)
You'll have to battle with your dragon companion against normal soldiers and, most importantly, huge monsters which require strategic thinking. (gearnuke.com)