Persona 3 Portable is Atlus latest port of an older Persona game to the PSP system. In truth with as much of a complete redesign and the staggering amount of added content this game is really a remake. P3P manages to keep everything that made the original such a classic and then adds all the fixes from Persona 4 then adds onto that even more improvements. If everyone made ports or remakes like Atlus gamers would be so much happier.
The story is virtually the same except instead of just playing as the main character from the PS2 version you have the choice between him and a brand new female protagonist with glowing red eyes. The differences here seem only like menu changes at first but the two heroes have very different experiences to share with you. The female main gets some story decisions late game that take the story on a slightly different path, while what you got from the male in the PS2 version is the same.
The basic premise of both gendered tales is that your a new transfer student who has the potential to summon demons because you can be awake during the Dark Hour. Instead of simply being midnight, the dark hour is a 25th hour that takes place at midnight. Here demons roam called Shadows, your school turns into a giant fortress of demon kind, and regular people turn into giant coffins. The story has your character join a team called SEES to find out the mysteries of the dark hour.
Back from the PS2 release is the awkward way of summoning your personas, which usually is through cards but in this game characters shoot themselves in the head with a device called an Envoker. The Envoker is shaped like a gun and it never becomes normal to see your characters blast themselves in the head, though amusing to see some characters not even question this including your main character.