Middle-earth: Shadow of War takes the best parts of its predecessor and gives them room to breathe. It's a sequel that opts to expand rather than alter, but that's fine when Middle-earth: Shadow of Mordor debuted with such strong core mechanics.

Those of you who played the first game will find yourselves in the familiar boots of Talion – an undead ranger who was murdered alongside his family by the forces of that pesky Dark Lord Sauron. Sharing his body with the wraith of an incredibly powerful elven warrior, Talion's out to put a stop to Sauron once and for all. The nations of mankind hang in the balance as our hero hops around Mordor killing high ranking orc generals and building his own ugly army.

Shadow of War tells a better story than its predecessor. It features a large amount of well directed and well acted cutscenes, and a wider cast of secondary characters help give the plot a better sense of purpose. While it's nothing amazing, the narrative is good enough to get you somewhat invested, and there are a few standout moments where the story successfully heightens the stakes.

For an action game it's enjoyable stuff, but devout The Lord of the Rings fans may take issue with some of the creative liberties that developer Monolith takes with information and lore gleaned from the source material. We don't think that there's anything especially blasphemous here, and it's clear the that studio has a passion for Tolkien's work, but there are moments where, if you've studied the books and immersed yourself in Middle-earth before, you'll likely raise an eyebrow or two.

Unfortunately for Shadow of War and its story, proceedings are held back by some uninspired mission design. Main quests are generally quite boring in terms of structure, tasking you with completing mundane objectives before you can lay your peepers on another cutscene. The plot's pretty lengthy, but a lot of that length stems from story missions that can feel like filler.

It's not that these missions are awful, but their flaws are highlighted by the fact that Shadow of War is so much fun elsewhere. Outside of core quests, the game offers up a selection of open environments for you to play around in, and this is where the release really comes into its own.

Everything is once again built upon the Nemesis System – an intricate and thoroughly impressive creation that the developer revealed in Shadow of Mordor. The system's put to even better use this time around as Talion forges dynamic relationships with randomly generated orc captains. At its heart the Nemesis System remains the same, but so much variety and spice has been added that it's really evolved into something special.

The open environments that we mentioned earlier are populated with armies of orcs. The vast majority are generic footsoldiers who patrol the land and have a terrible habit of sitting way too close to explosive barrels, but these grunts are headed by captains – named orcs who have individual abilities and skills. As Talion, you'll constantly be working to hunt down captains and decide their fate.

It's this decision making that influences the Nemesis System as a whole. Once you find your target captain, it's time to choose: does he die, join your cause, or flee in shame? Whatever path you take, there are usually consequences. Captains that you kill can come back later to take revenge, this time with a huge scar down their face and perhaps a missing arm. Orcs that you've branded, forcing them to side with you, may try to stab you in the back further down the line.

The way that the Nemesis System takes all of these potential interactions and turns them into their own unique substories is fantastic. Forging personal narratives with the many monsters of Mordor is what keeps the game ticking, and the system provides a massive amount of replay value to boot. However, it's this free-form storytelling that casts a shadow on the aforementioned main quests. You end up getting so invested in your unique roster of orcs that the main plot can start to feel like it's getting in the way – like it's been nailed onto something much more interesting. And again, that's not to say the story is bad, rather it shows just how brilliantly engaging the Nemesis System is.

Fortunately, you can play around with the system as much as you want, particularly once you've mopped up the main story. After the credits roll, you see what the Nemesis System is truly capable of in the Shadow Wars endgame. Here, you're free to continue conquering Mordor however you see fit, and without any distractions, the tangled web of relationships seems to stretch on endlessly.

All of this is of course tied to a fast and fluid combat system, which really hasn't changed much from the first game. Talion flips and slashes across the battlefield in style, and the animations still look great. As with any contextual combat that sees you react to your opponents by hitting the right button at the right time, things can get slightly awkward as you glitch out every now and then, but overall, the system's still a lot of good, bloody fun. It's also bolstered by a welcome loot system, even if there's not that much depth to it.

Shadow of War is a huge game that you can get lost in for hours on end, but if you find yourself wanting to wreak some extra havoc, you can always check out the title's online features. Connect to the Internet and you can test your skills against captains from the games of other players, or you can assault fortresses prepared by fellow users with the armies that you've cultivated. These missions are entirely optional, but if you're hungry for further action, they're nice to have around.

Successful online escapades reward you with loot boxes, and this is where we have to talk about microtransactions in Shadow of War. Right off the bat, we'll say that the loot boxes feel out of place, and not just because this is a single player game. Going to a separate menu screen just to open them up makes it seem like they've been haphazardly bolted to the experience. Can you complete the game without ever opening a loot box? Absolutely, but that doesn't change the fact that they've been jammed into a title that definitely doesn't need them. Whether you use them or not, seeing that little marketplace tab on the main menu cheapens what is otherwise a great game.

On that note, it's worth pointing out that much of what's impressive about Shadow of War hides beneath its surface. Now, it's certainly not the best looking game in the world. Lighting can appear far too flat at times and locations can come across as monotonous, but the engine is capable of some spectacular feats, namely when you're charging into battle with dozens of orcs by your side and watching as they clash with the opposing army. It's almost Dynasty Warriors-level stuff but much more intricate, and the framerate stays rock solid throughout.

Conclusion

Middle-earth: Shadow of War is stellar sequel to a surprisingly great game. The Nemesis System remains the real star of the show in all of its expanded glory, and while its dynamic brilliance threatens to make the main story missions seem boring by comparison, there's enough heft to the overall package that you can look past its shortcomings. In the barrage of blockbusters hitting PS4 over the next few months, Shadow of War should not be missed.