Atlus has given 3DS-owning RPG fans plenty to be excited about recently, with Etrian Odyssey IV and Shin Megami Tensei: Devil Summoner: Soul Hackers both released this year alone. Now the latest entry in the mainline Shin Megami Tensei series has arrived to complete the dungeon-crawling hat-trick, bringing its unique brand of demon summoning and dark, multilinear storytelling to Nintendo's dual-screened darling. This is a sequel fans have been waiting nearly a decade for, and we can't imagine anyone will be disappointed; Shin Megami Tensei IV is deep, stylish, and incredibly fun.

Shin Megami Tensei IV casts you in the role of a young, newly minted samurai serving the Eastern Kingdom of Mikado. Mikado samurai have the unenviable task of keeping demons from encroaching into the human world, so with the help of your sentient gauntlet (and its sultry AI component, Burroughs) and three fellow 'prentices', you'll set about your training. Things get weird very quickly, however, and it's not long before your group finds itself in the strange land of Tokyo, desolate and overrun with demons, on a very different mission.

We don't want to spoil a thing - the less you know going in, the better - but the story's quite a ride, and while it evokes common themes of class conflict, morality, friendship, and death, this is far from the usual save-the-world scenario. It's also occasionally disturbing; the game earns its M rating from the plot as much as from its nearly-nude demons.

It won't be the same story twice through, either; branching storylines are a hallmark of the Megami Tensei series, and each of your three companions rather transparently represents a different path - Law, Chaos, and Neutrality. The choices you make throughout the game will directly affect the outcome, which lends an exciting gravitas to every selection box.

The writing is excellent, and what at first seems like extremely stilted translation (as when the badass Chaos character uses the words "fop", "galling", and "demur" in the same sentence) actually helps to characterize this alternate reality where no one's heard of guns, France, or "literature". Voice acting for nearly every line brings the world and its inhabitants to life, and though the NPCs' delivery can be a bit hammy, the main characters are very believable.

Just under the surface of this well-realized world is a third-person dungeon-crawling RPG, featuring turn-based combat and a quest system that puts a premium on exploration and forward momentum. You'll take on Main Quests - large and small - to advance the storyline, as well as a huge number of optional Challenge Quests, picked up at bars and hunting associations throughout Mikado and Tokyo. Ostensibly side-quests, the Challenge Quests are often just as absorbing as the main missions, and offer up a wide variety of tasks, from demon slaying and deliveries to escort missions and item collection - some even have a direct effect on the outcome of the story.

The branching story and its human protagonists are interesting enough, but the real stars of the show are the demons you'll meet, fight against, and command in battle: a huge cast of characters made up of figures from religion, lore, and mythology the world over - Native American, Japanese, European, Polynesian, Chinese, you name it. They run the gamut from gallant to grotesque and everything in-between, and they're universally enchanting. Wonderful portraits, quirky dialogue, and individual voice acting give them an enormous amount of personality, and a Profile tab gives you the lowdown on each demon's cultural context, which makes having them by your side in battle that much cooler.

Getting the bewitching beasts on your side means engaging in a staple of the Shin Megami Tensei series: demon negotiation. Instead of simply capturing them or wearing them down in battle, you'll have to talk them into joining you, and it can be an interesting process. Every demon has its own quirks, which you'll need to learn and take into account in your chats: some demons are proud, and want to feel superior, others want to be impressed by your strength, some will flirt with you and expect you to flirt right back, and others just want to make some quick Macca - the demonic currency of choice.

Once you've assembled a respectable collection of demons, you can fuse them together to create new, higher-level allies with the help of Mido, a voxel-rendered old man with a long beard and a Max Headroom glitch. Demons can pass on their skills in fusion, and performing multi-step fusions to craft the perfect set can be surprisingly addictive.

The demons are interesting enough that simply collecting them could carry a game on its own, but you'll spend most of your time directing them in combat. There aren't any random encounters here; instead, enemies appear as ghostly, pixelated figures roaming dungeons and the streets of Tokyo, and it's up to you to initiate a battle with a satisfying slash of your samurai sword. Enemy demons can do the same, however, so you'll need to keep on your toes to avoid being ambushed from behind.

The battle system is based around eight elemental strengths and weaknesses, with physical, gun, ice, fire, force, electric, light, and dark attacks all coming into play. These elements are at the heart of the 'Press Turn' system, which rewards combatants with extra turns for exploiting enemy weaknesses or scoring critical hits, and takes away turns for whiffed or reflected attacks. After a particularly powerful hit, you might even see a "smirk", a special status condition that raises defensive and offensive power on the next turn.

Mastering the Press Turn system is the single best way to come out ahead in battles, and it's hugely fun to take advantage of; with the right party for the job, it's possible to get eight attacks in on an opponent before they can even move. The focus on exploiting weaknesses also makes this significantly less grind-heavy than most dungeon crawlers - combat is much more about strategy and elemental advantage than it is about levels and raw power, and that makes for lots of satisfying David vs. Goliath fights.

Of course, the flip side of the system is that if an enemy catches you off-guard and manages to exploit your weaknesses, your entire party can easily be taken down in a turn or two. It's not all over if that happens, however, and dying doesn't even necessarily mean a Game Over screen. As it turns out, Charon - the man responsible for rowing dead souls across the River Styx - is a pretty soft touch, and can be bribed with either Macca or Play Coins to look the other way as you scamper back to the land of the living.

After you've been to Hades and back twice (which, for us, happened in the game's second tutorial mission), you'll unlock the option of playing on Easy Mode. While you'll still live and die by the Press Turn system and finding enemy weaknesses, this mode tips the damage scales subtly in your favour. It makes the game much more accessible for beginners, without taking away any of the depth of the combat system.

Whichever difficulty you chose to play on, you'll be able to tailor the game system to your liking with Burroughs' 'Apps'. You'll earn 10 "App Points" with each level gained, and you can spend these however you like - upgrades include space for more demons or skills, negotiating tools, experience boosters, and hacks to lower MP costs, raise the level ceiling for demon fusion, or even regenerate HP or MP as you walk.

It isn't just demons that can use magical attacks, either, and you can choose which skills your character learns via "Demon Whisper": as your demons level up and learn new skills, they'll offer to teach them to you. It's a totally charming replacement for a skill tree - the demons are very proud of their Whispering, and will try to talk you into taking more - that fits the game perfectly, and a constant reminder that you're only as strong as your demons.

Graphically, Shin Megami Tensei IV is characterized by a smorgasbord of different presentation styles. There's the 3D third-person exploration of dungeons and smaller areas of Tokyo, the first-person combat with two-dimensional sprites on 3D backgrounds, the menu-based towns, shops, and bars, and the larger overworld of Tokyo, traversed from overhead as you move a stylized marker around a map. NPCs can either be sprites, 3D models, or invisible until spoken to - but once you engage them in conversation, they're nearly always represented by small, static sprites with indistinct faces. More important exchanges - particularly those with your teammates, or demons - use beautiful, screen-filling character portraits, enlivened by a Ken Burns effect.

The 3D environments are stunning, especially with the in-game augmented-reality system that points out signs, doors, and items of interest, sending neon circles of light zeroing in on your character as you approach them. And though we're not crazy about the menu-based town navigation in Mikado - it's efficient, but immersion-breaking - we love the symbolism of the switch to a 3D overworld coinciding with the samurai's arrival in Tokyo's uncharted territory. The NPC sprites with blurred faces, on the other hand, are very similar to those found in Soul Hackers (originally a Saturn game), and while they have their charm, they feel distinctly 32-bit. Taken as a whole, however, these different approaches come together very well. It reminds us of the three representations of the characters in Fire Emblem: Awakening - rather than creating a hodgepodge, it gives the game a great sense of stylistic variety.

The stereoscopic 3D effect adds a lot to the presentation, but it has a few issues; some of the larger demon sprites tear across layers very easily, and menu elements are jumpy enough that it's often hard to tell where they're supposed to sit in terms of depth. Then there's the fact that certain 3D sequences - like the demon fusion animation - take place on a single, flat plane, missing the stereoscopic effect entirely. These are mostly minor quibbles though, and it's definitely worth playing with the 3D effect on, even if it means adjusting the slider every once in a while.

Shin Megami Tensei IV excels in atmosphere, thanks in large part to the soundtrack. The martial pipe-and-drums theme of Mikado Castle will linger in your head long after you've left its familiar confines, the slightly sinister demon fusion theme lends an appropriately occult air to your alchemy, and once you hit Tokyo, there's a steady stream of slick, futuristic tunes that call to mind the best melodic moments of Soul Hackers. The audio quality is excellent too, and this is a game best experienced with headphones - the music, sound effects, and ambient noises come together to craft a truly enthralling aural environment. As a small example of the level of detail on offer, we were blown away when we realized the sound of our character's run changed depending on the armour he was wearing.

Finally, a StreetPass feature dubbed the "Digital Demon Service" lets you share a profile card and an attached demon with your fellow samurai. This demon can grow, return with gifts, and even fuse into new forms as you StreetPass, but as long as it's attached to your DDS card, you won't be able to summon it into battle. That makes sense, as it's potentially growing and changing on its DDS travels, but it would be nice if the attached demon didn't continue to take up valuable space in your stock. Still, we expect this will be a fun addition for players who can take advantage of it.