The Persona series, an offshoot of Atlus's long-running Shin Megami Tensei franchise, was a changeup for not only JRPGs as a whole but for the franchise it spawned from. Earlier games were set in a dystopian future where the world is overrun by demons and those working alongside them to enforce their will on the world, while Persona was more of a traditional JRPG - still set in modern times, but with a clear-cut villain for the protagonists to face and defeat in order to prevent a catastrophe. However, they still retained the series' defining trait - being able to recruit and fuse demons, though they now served the role in a more indirect fashion in Persona - personae were now linked to the human characters, determining their stats, elemental strengths and weaknesses, and what spells they could cast in battle.
Persona 3 continued the trend, albeit in a somewhat more limited form - while the protagonist could still have multiple Personae and switch between them at any time during combat (adopting their skillsets and stats in the process), the other party members' abilities were more static, sticking with a single Persona throughout the game that would only change as the story dictated. Other mechanics, like the Nuclear element and the secondary gun weapons, were exhumed entirely in favor of simplifying weapons to one of three times (strike, pierce and slash) and giving most characters access to only one, encouraging the player to diversify their party as boss battles dictated. Each was also balanced out in its own way, generally by trading off power or accuracy. Akihiko's boxing gloves, for example, are one of the weaker weapon types, but have a very low chance to miss, while Misturu's one-handed swords were average in both accuracy and damage. One odd outlayer was Yukari's bows, which were average in damage and relatively low in accuracy, but had a unique advantage in that a missed shot would not result in her being knocked down.
Persona 3 also incorporated a controversial element of some of the later main-line Shin Megami Tensei titles in the "One More" system. A somewhat more forgiving version of the Press Turn system from Nocturne and Digital Devil Saga, the game would grant a character (whether friend or foe) an extra turn for scoring a knockdown on an enemy, either with a critical hit or by exploiting an elemental weakness. Unlike the Press Turn system, however, this only affects that particular character - the rest of the team does not lose their turns when an attack is absorbed or reflected, nor can extra turns be passed to other characters. This can prove problematic in some fights - if a particularly strong enemy hits a character's weakness, they'll typically follow up with another heavily-damaging attack on the following turn that can devastate the party, if not kill them outright. On the other hand, this does allow the player to quickly sweep through many weaker enemy encounters once they discover enemies' weaknesses, allowing them to navigate the dungeons rather easily so long as they take care not to get surprise attacked. In this way, the One More system keys well into the game's challenge, rewarding the player for diligence and forcing them to improvise when they're caught in a situation where a party member with a particular weakness can easily become a liability.
Persona fusion itself saw an overhaul in the third game as well. Exhuming the tarot card collecting and trading element of the first two games, Persona 3 takes it in a direction more similar to classic Shin Megami Tensei, with the player randomly earning Personae for their main character after winning a battle or by fusing two (or more) together in the Velvet Room to create a new one. As in Nocturne, some spells and abilities can be carried over to new-generation Personas, allowing the player to more carefully customize their party and adapt strategies for upcoming fights.
Tying further into this is the game's Social Link system, a first for the series. The game's main storyline proceeds in a linear fashion, with time passing day-by-day and new events coming up on specific dates. However, the player is frequently given free reign to decide what they want to do with any given day - boosting social qualities, exploring the game's main dungeon (Tartarus) or, most significantly, meeting friends and teammates to build Social Links. These scenes give a bit of a story arc for many of the major characters in the game, but also intrinsically tie into the Persona fusion mechanic. Each Social Link formed is linked to one of the twenty-two Arcana that Personae comprise, and by gaining levels in that Social Link, the player will gain bonuses by fusing personae of that Arcana, allowing them to gain up to five levels right out of the gate. Once a Social Link is maxed out, the ultimate Persona of that Arcana becomes available for fusion. These tend to be extremely powerful Persona with few or no elemental weaknesses and several top-tier skills, making them invaluable allies, particularly near the end of the game.
Persona 3 clearly puts much focus on the game's main character, making him the center of the story as well as the focus of many of its mechanics. However, this also results in some less-liked design elements of the game. The player is only given direct control of the main character, with the rest of the cast acting according to any of several AI directives at the player's command (things like attacking freely, targeting enemies' weaknesses, or supporting the party). While the party AI isn't bad for the most part, it does have some irritating shortcomings at times; namely that they will continue using basic potions well into the late stages of the game (restoring only 50 HP, which isn't much), and that they have an annoying tendency to spam ineffective spells (like Charm) or target all enemies with elemental attacks even if only one is weak against it, resulting in wasted MP and potentially extra turns. Another, more annoying shortcoming is the fact that if the main character dies, the game ends immediately - another character cannot revive him after or even during the fight, even if they have a spell for exactly that purpose. This can be frustrating at times, particularly if you make a lot of progress in Tartarus in one go and get punked out by a surprise attack or an unexpected elemental weakness exploitation by a boss.
Some other rough edges creep into the game's design as Atlus was still cutting their teeth on this new style of gameplay. While combat in the game is enjoyable and engaging despite its repetitious nature, the game's central dungeon itself (Tartarus) is rather monotonous to explore, being comprised of little more than randomly-generated mazes with a boss fight every twelve floors or so. Social Links themselves make for an enjoyable element of game design and character development, though in many cases, the correct lines of dialog to pick are pure guesswork without a guide by your side (which can easily prove problematic if you're going for the game's ultimate Persona, which requires maxing out all Social Links in a single playthrough). Finally, the game provides various side-quests to complete, usually initiated by talking to Elizabeth in the Velvet Room - unfortunately, these generally just boil down to hunting and defeating various enemies in search of random item drops, or speaking to specific people on specific dates with no second chance afforded to the player if they forget. Thankfully, the rewards they give are by no means necessary to complete the game, though they do prove quite useful on a first playthrough, which can result in relatively long stretches of game spent completing menial tasks in order to be prepared for an upcoming battle.
Despite a few rougher elements, however, Persona 3 is an excellent game. Its innovative gameplay design encourages developing one's bonds with the main cast, its combat is engaging and it provides enough depth, strategy and challenge for the most die-hard of RPG fans out there with its multiple difficulty levels and intricate Persona fusion system, as well as some monstrously tough optional challenges that can only be attempted on a second playthrough or later. Few games can keep themselves from falling prey to diminishing returns over an 80+ hour runtime, but Persona 3 pulls it off, delivering an RPG experience that remains engaging thanks to its gripping story, strong characters and well-planned design. Persona 4 would later polish up its gameplay and take its character development and storytelling to new heights, but Persona 3 is still very much a game worth your time.
Developer: Atlus
Publisher: Atlus
Platform: Playstation 2, Playstation Portable
Released: 2006, 2008, 2010
Recommended version: Persona 3 FES is an excellent re-release on the Playstation 2 that adds in a bevy of new content including many new quests, a weapon-crafting system, a new ultimate Persona, an extra Social Link, and even a sequel story called "the Answer" that picks up right where the main game ends. Persona 3 Portable on the PSP lacks The Answer and has a few features stripped out to save space (most of the animated cutscenes and limiting the protagonist to a single weapon type), but uniquely has an alternate female protagonist with her own set of social links and many different dialog scenes, as well as the ability to have full control over all characters in battle, rather than just the protagonist. There is unfortunately no definitive release that combines all of these features together in one package (yet), so I'll have to recommend two versions here - Portable for the polished up gameplay and extra features, and FES for the extra story chapter.