Something of a sequel to Sword Art Online Re: Hollow Fragment, Sword Art Online: Lost Song carries on the legacy of the previous game, featuring returning characters and references to past events. Fans of the original Sword Art Online light novel or adapted anime will, of course, feel right at home, while those who enjoyed Hollow Fragment will also find a lot to like. For everyone else, though, Lost Song is a title that demands a bit of prior knowledge to fully appreciate.

Despite some attempts at introducing protagonist Kirito and his chums through flashbacks and various instances of dialogue, it's not quite enough to welcome newcomers to the property and its world. The story, too, won't carry much weight unless you're familiar with the cast to some degree – although having said that, the plot itself isn't anything particularly special to begin with.

Taking place after the events of Re: Hollow fragment, Kirito and the gang have all started playing Alfheim Online – another virtual reality massively multiplayer online game that has a lot of similarities to Sword Art Online. It's got monsters to slay, quests to complete, and rare items to find, but death in this digital world no longer means death in reality – you're playing a game as a guy who's playing a game, which, in some cases, can make it hard to truly care about what's going on. Kirito's never really in peril – all he has to do is log out and he'll be fine – and this has a knock-on effect in that the narrative doesn't quite hold the dramatic tension that it should.

It's a bit of a shame, too, since the interactions between the cast are well done, but there's just this pervading knowledge that they are, ultimately, just a bunch of teenagers playing a video game. That said, the kind of behaviour that's perhaps stereotypical of MMO players is represented well, and anyone who's dabbled in the genre will probably nod knowingly at some of the writing that highlights this.

With a narrative that's slightly difficult to become genuinely invested in, it's a good job that Lost Song's gameplay holds up. Unlike in Re: Hollow Fragment, the game's world is split up between different floating islands, each of which are vast and open. By completing chapters of the story – which you can tackle at your own pace – you'll gain access to the next island, which creates a kind of stage-based structure. It's a departure from the connected areas of the last title's sprawling setting, but there's still a nice sense of adventure and exploration – especially since there are treasure chests and points of interest scattered about each map.

Traversing these locations is a breeze, too, thanks to the fact that Kirito and his buddies now have wings. By tapping right or left on the d-pad, you'll be able to hover in mid-air, and by tapping up, you'll shoot off into full flight. Zipping around the world from the very beginning of the game is a refreshing change of pace when it comes to RPGs in general, and although it can take a little while to get used to, switching between standard ground movement and flight is just simple fun.

Whether in the sky or with something solid beneath your feet, monsters will almost always populate the immediate area – and there are a lot of them. You could quite easily fight your way from one end of the map to the other without much pause if you so desired, which is great for grinding experience and items, but it makes it feel like you're never free to wander around and take in the pretty scenery.

Thankfully, combat is largely enjoyable, which at least means that hacking and slashing your way through hordes of foes to reach the next dungeon doesn't feel like a chore. Distancing itself from the strangely compelling hybrid of Re: Hollow Fragment's button tapping combos and MMO-like ability cooldowns, Lost Song goes full action, allowing you to mash square and triangle to make mincemeat out of your foes while either dodging or blocking incoming blows.

All in all it's a standard 3D fighting system that's easy to get to grips with; its complexities end at keeping an eye on your stamina and magic bars, which are used up when you perform special attacks or spells. Consequently, combat doesn't offer a huge amount of depth, but its real-time action is enough to keep you engaged. Likewise, surrounding RPG mechanics such as levelling up, learning new skills, and discovering better equipment are nothing out of the ordinary, but they still make for a rewarding sense of progression – especially when you hunt down previously tough opponents and clobber them with your powered-up party.

Speaking of party members, you'll always be accompanied by up to two of Kirito's friends, and you can even choose to control one of them this time around, which can add a little bit of variety to your adventures. The artificial intelligence is competent in battle, and your buddies will sometimes casually chat among themselves, often providing commentary on your current task. The additional dialogue is just a small touch, but it's a welcome one, sprinkling some flavour on quests that otherwise don't do much to differentiate from the typical formula of 'go there, kill this'.

Side quests and generally tougher extra quests are usually worth following through for the rewards that they offer, though. Loot is reasonably common in Lost Song, but stumbling across a rare weapon after a lengthy boss fight feels every bit as good as it should, and taking your goodies back to town in order to identify them creates a very addictive gameplay loop.

And if questing for precious gear with virtual allies isn't your cup of tea, you can always hop over to the multiplayer side of things. This time around, you can either take on powerful boss monsters with a party of up to four other players, or you can test your skills in competitive fights. The former is a decent amount of amusement if you team up with people who actually know what they're doing, while the latter jumps between two extremes: it can either be quite tactical with teams of four bolstering each other's abilities, or it can be absolute chaos, with players flying all over the place and unleashing every kind of technique that you can imagine. In short, it can be a bit of a mess, but there is some fun to be had.

Conclusion

Sword Art Online: Lost Song plays it safe, but there's nothing necessarily wrong with that. Combat and quests could stand to offer a little more depth, but there's still an enjoyable, addictive RPG to be found here, and it's topped off by a refreshingly pleasant means of traversal in your ability to sprout wings and take to the skies. Primarily a game for fans, Lost Song obviously won't appeal to everyone, but those who do enjoy the source material will certainly appreciate its colourful and inviting world that's packed with things to do.