The PlayStation Vita has a formidable catalogue of Japanese role-playing games that always seems to be expanding, but it's fairly easy to make the argument that Ar nosurge Plus is one of the better additions. An enhanced port of the PlayStation 3 title which released last year, it's an enjoyably unique adventure that boasts an entertaining story.

The game's set on a huge spaceship that houses the remnants of a destroyed planet. Even just after the opening cutscene, it's clear that there's quite a lot of background information to take in, and as such, it can take a few hours for the narrative to really click. Once it does, though, you'll discover a well paced tale that twists and turns as it follows the events that transpire between two opposing factions.

On one side of the ship, a religious order that believes mankind should work together with monsters known as Sharl seeks to purify non-believers by force, while across the border, people are ruled over by an Empress who seeks to protect humanity from anything that would seek to cause it harm. The ideological differences make for some surprisingly thought provoking plot points, and all in all, it's a story that you'll want to see through once you wrap your head around it.

The cast's quite endearing, too. At first, the characters, including those you play as, can seem a little too typical of what we expect from mediocre anime, but as the narrative progresses, almost every personality really comes into their own. This is mostly thanks to the huge amount of dialogue that you'll have to sit through, but even though it can certainly seem like a slog at times, the interactions are ultimately worth experiencing for the eventual emotional payoffs that occur throughout.

It's the relationships between the two sets of main characters that really steal the show, though. At a certain point relatively early in the game, you're handed the ability to switch between Delta and Cass – childhood friends who now serve the Empress as special agents – and Earthes and Ion – a mysterious robot and his master. There's obvious romantic tension between the former, while the latter's especially interesting because it puts you, the player, into the role of mechanical man Earthes. Of course, to explain much more would be to spoil things, but let's just say that Ar nosurge Plus particularly enjoys dropping seemingly nonsensical plot points into the story, only to come back to them later to really blow some minds.

You'll also get to know your leads through the purification ceremony, in which your current duo take a hot springs bath together. While soaking, you'll be able to initiate conversations with your partner, getting to know them better while also unlocking new ways to power them up. New conversation topics are found throughout the game, and sitting down to casually chat provides a nice change of pace after a hectic slice of story. It's a bit of a shame, though, that the title feels the need to titillate with heavy handed sexual innuendos. There's obviously nothing wrong with some comedic flirtation here and there, and that's actually something that the release handles well, but there are points where some players will deem the practice unnecessary.

We've already mentioned that there's a massive amount of dialogue included in the main plot as well as during the purification ceremony – especially since Plus comes with the fresh option to bathe with other members of the cast as well as your partner – but there's yet more to be found when diving into the minds of other characters. One of the game's main concepts is song magic, a powerful kind of energy that can be harnessed by certain individuals. Both Ion and Cass can make use of song magic – mainly to defeat their enemies – while Delta and Earthes act as their protectors during combat. However, to strengthen the heroines' song magic, Delta and Earthes have to maintain a healthy bond with their partners.

It sounds crazy on paper, but to truly understand your allies, you'll have to enter their subconscious minds and resolve any doubts or fears that are holding them back. By defeating enemies in battle, you'll collect dive points, which can then be spent to explore your friends' heads. The system essentially plays out like a visual novel, as you move from one part of their mind to another, interacting with the usually ridiculous personalities that they've fabricated. It's an intriguing concept, that's for sure, but its execution is somewhat clumsy. Many scenarios see you making dialogue choices, and sadly, trial and error often plays a part when it comes to working out which choice is the right one. Still, diving does help flesh out the cast, even if the process can be a bit arduous.

Moving onto combat, Ar nosurge Plus boasts a frantic battle system that makes for a welcome change of pace after reading through reams of dialogue. You only ever enter brawls as your currently selected two main characters, and even then, you only take control of either Delta or Earthes. True to their cause, your job is to protect your song magic-wielding partner as they harmonise with your actions. Rack up some combos with the face buttons – which are each assigned to a different attack – and the harmony gauge will rise. It'll fill quicker the better that you do, too, so success lies in your ability to stun enemies that are marked to attack next. By doing so, you'll gain an extra turn, and you'll be able to let loose with all of your techniques once again.

Because you're always trying to lay waste to as many foes as possible before you run out of moves, battle conjures up a satisfying rhythm, especially when you've levelled up and gained access to a broader range of abilities. However, your opponents attack in waves, so once you've obliterated one group, another will slide into place. Most of the time, you'll probably have to deal with around ten or so waves before you seize victory – but this is where song magic comes in. As you beat your foes to a pulp, Cass or Ion will gradually begin to help out by blasting remnants with magic, and when your harmonics are completely in sync, you'll be able to unleash a devastating song that annihilates any waves of enemies that are left. Again, it's yet more reason to go on the offensive as effectively as possible to build up that harmony gauge, and with various different song magics to unlock via diving, battles almost always end on a satisfying note.

With such an enjoyable battle system, you'd perhaps expect better of the rest of the title's RPG mechanics, which are found to be disappointingly lacking. Equipment, for example, rarely plays a part, and even though there's a simple crafting system in place, it's just not utilised enough because recipes for new gear or items are too few and far between. The groundwork for a more in-depth RPG is present and correct, but surprisingly, it's just never truly build upon. As such, you're really just left to level up your party with experience gained from battles, and you never truly notice any growth in power aside from when you unlock new techniques to use during combat.

The real kicker here, though, is the equally disappointing technical performance. The Vita release looks nice and crisp on the handheld's screen; it boasts plenty of colour, and the art style is original and really quite eye catching – but it's hampered by some annoying frame rate issues. When running through one of the title's few towns, for example, the frame rate tends to chug considerably, and it's just a pain when you consider how good the release can otherwise look. Fortunately, the frame rate does hold up in battle, where it matters most.

In a game that's all about song magic, you'd hope that Ar nosurge Plus' soundtrack's a good one, and thankfully, it is. Combining some Eastern instrumentals with plenty of electronic beats, this is definitely a job for a good pair of headphones. The battle themes are particularly enticing, while much of the ambient music sets the tone well. Meanwhile, the English voice acting is handled admirably, but it's worth noting that the release does include the original Japanese voices, too.

Conclusion

Ar nosurge Plus is a surprisingly unique experience that's bolstered by an interesting art style and a great soundtrack. An overbearing amount of dialogue can sometimes cause proceedings to drag, but an endearing cast of characters make the story worth sticking with – especially once you wrap your head around the game's strange world. And, while the title's RPG mechanics leave something to be desired, the satisfyingly pacey battle system is usually on hand to restore your faith. Although it doesn't quite reach the heights of a surging opera, this Vita re-release is still worth singing along to if you're a fan of Japanese RPGs.