Operation Abyss: New Tokyo Legacy might not sound like a familiar name, but the core gameplay will be familiar to anyone who's previously played the Vita dungeon crawler, Demon Gaze. Both games were made by Experience Inc., a Japanese RPG developer who specializes in dungeon crawlers. Operation Abyss is actually a remake of Experience Inc.'s first two games: Generation Xth: Code Hazard and Generation Xth: Code Breaker. It's an old-school dungeon crawler that's set in a modernized sci-fi setting instead of the dungeon dwelling of dragons and monsters.

As mentioned, Operation Abyss is set near modern-day Japan. The country is under mysterious assault by monsters called Variants. They appear in otherworldly dimensions called Abysses, which transform normal buildings into labyrinths to serve as Variant hives. The only force that can stand against these monsters are Xion Transhumans, or teenage boys and girls who can transform into armored superhumans. Together, they form the Xth Squad and work together with the Code Physics Agency (CPA) to handle the hazard cases that arise when Variants attack. There's more to Variants than random monster attacks, and it's up to the Xth Squad to figure out what is causing the attacks before all of humanity is lost.

While there's a healthy dose of named characters, none are part of your player squad. Instead, your squad is comprised of player-created characters — named Abyss Company by default. Creating characters is a surprisingly complex process. You begin by setting up the basics: name, appearance, and so on. Players have an option of using either classic character art, which is simplified but can be customized, or more complex character art created specifically for Operation Abyss, which is more detailed but can't be customized. Once you choose your basics, then you have to set up your personality traits, which are extremely important because they determine the sort of blood codes you can equip. Finally, you set up your default stat lineup by picking a character type, which ranges from average to funny to unlucky.

Blood codes are effectively the game's classes. They're a take on the classic roles that you can see in most Wizardry-style dungeon crawlers: knights, samurai, wizards, etc. Some have slightly different names than you might expect — rogues are called academics, for instance — due to the use of locked data instead of traditional dungeon treasures. A blood code is tied to a specific spirit that your character can bond with, and each spirit is the heir to the legacy of a famous hero, including Leonardo Da Vinci to Hattori Hanzo and Genghis Khan. Each blood code has a set of skills and stats. You can even swap different blood codes to add some flexibility. Characters earn boost points, as they gain levels that can transfer between blood codes for further customization, although you can only gain additional points if your equipped code gains a higher level than your previously equipped one.

The dungeon crawling in Operation Abyss may feel very familiar to veterans of the genre. The entire game takes place in first-person perspective, and you wander through increasingly complex dungeons trying to complete various missions. Each dungeon has traditional dangers and traps. There are floors that hurt your party, spin you around, or leave you trapped in the dark. There are also hidden areas to explore, and secret passages you can use. You can check the map at any time, and similar to Demon Gaze, you can auto-pilot to any location you've previously visited.

Operation Abyss features some interesting twists to the dungeon crawling mechanics. Since you have limited casts of spells, you're often encouraged to back off as soon as you start to get low. However, the Rise & Drop system makes that less simple. As you fight, you'll notice the encounter gauge increase, and as it does, you attract more dangerous enemies. However, those enemies also drop better loot, and you're more likely to encounter rare enemies. The downside, of course, is that enemies get more powerful. You can reset the gauge by running from battles or by defeating a Wanted enemy. Maintaining a balance between strong foes and survivable fights is a big part of the game. Also similar to Demon Gaze is the ability to leave memos on the ground, which appear in other players' games and can provide tips and hints.

In combat, you have two lines of three characters, and you can access their basic abilities. One thing that may feel odd is the inclusion of classic D&D-style spell slots. Rather than having MP to cast abilities, you have a limited number of spells per tier, and you can spend them on any spell in that tier. It makes magic more restrictive, though you have methods to replenish MP to make it more viable. You also have access to powerful unity attacks, which use a special bar that fills as you battle enemies. They're the strongest tool you have but require careful planning so they're not wasted. A good unity attack can turn around a bad fight, but it takes a long time to recharge.

Careful planning is the name of the game in Operation Abyss. You have to carefully balance between venturing further into the dungeon and returning to base. The game strongly encourages you to not stay out too long. You can't level up until you return home and rest, and early on, magic replenishment is rare. Returning home allows you to use material that you've found in the dungeons to craft new items, so you can return more powerful than before. The robust customization system allows you to craft, upgrade and customize equipment to specialize against various threats. You also can't play too cautiously. Operation Abyss has a level cap that only increases as you advance. Hang around too long, and you'll hit your plateau and need to advance to get stronger. You also risk losing party members if you're not careful. While an annihilated party can be rescued by spending money, a dead character left in the abyss can be lost forever.

Operation Abyss: New Tokyo Legacy is shaping up to be an enjoyable old-school dungeon crawler. It's targeting the kind of folks who enjoy Wizardry-style character customization and dungeon diving, but it knows exactly what it wants to be. Some elements of the game may feel odd, even when compared to Demon Gaze, but there's still plenty of dungeon-crawling excitement to be had. The unusual sci-fi-themed story does a lot to help it stand out from the countless fantasy-themed dungeon crawlers on the market, and it may be enough to draw in some newcomers. Die-hard RPG fans will have a lot to look forward to when Operation Abyss hits the PS Vita on June 9.