French publisher Ubisoft is on its home turf with Assassin's Creed Unity. With a sprawling recreation of 18th Century Paris to explore, the game does away with Assassin's Creed IV: Black Flag's naval angle, and returns to a setting that evokes memories of Assassin's Creed II and Assassin's Creed: Brotherhood. With the French revolution kicking in as thousands of people take to the streets, Unity is perhaps the most chaotic instalment in the series yet – but this chaos comes at a terrible price.

This time around, you'll be sneaking and stabbing with Arno Victor Dorian, a cocky but dashing rogue who, for the most part, is a joy to play as. The surrounding cast isn't too bad either, and there are some genuinely decent attempts at characterisation throughout the story, but it's the plot itself that tends to falter as the adventure progresses. While the release sports some of the best acted scenes that we've seen in the franchise, much of the tale unfolds in a decidedly predictable way, and the worst part is that by the end, Arno has had his sharp personality whittled down by the familiar narrative of Assassins vs. Templars.

Fortunately, the modern day sequences, which continue the overarching plot of the series, are few and far between, and aren't nearly as invasive as they have been previously. Here, time anomalies take centre stage, and you'll need to navigate your way through distorted timelines in order to get back to revolutionary Paris. These sudden missions are linear, but they're relatively exciting, and although they do little to actually impact the story, they're nice enough additions that provide a bit of variety.

Still, the plot progression is just enough to keep you playing, but the real star of the show is Paris itself. Much like Brotherhood's Rome, the French capital is brilliantly crafted, and it's often a pleasure to simply walk the streets and take in the sights. Landmarks like the Notre-Dame Cathedral are stunning to behold in both scale and attention to detail, and scampering up them with Arno's agility feels fantastic.

Indeed, as far as the series goes, Unity easily boasts the best movement yet. Arno is decidedly lighter on his feet – the slightly weighty feel of previous protagonists is mostly gone – and as such, climbing up structures is accessible and impressively fluid. A slew of new animations also make our hero seem much more flexible as well, and, for the first time, it's now possible to easily hop down buildings by holding the circle and R2 buttons. In short, it's never been easier or more enjoyable to blaze your own trail through the dense sandbox settings that Ubisoft is so fond of crafting.

There are improvements to the formula elsewhere, too. In many ways, the game feels like it's attempting to refine the franchise's now predictable template, and by and large, it succeeds. Stealth has seen a slight overhaul thanks to a reworked cover system and a new sneaking stance that sees Arno crouch and make less sound, while combat is quite a bit harder. In previous outings, there was never really a need to run away from your aggressors. If you were being hunted down by a dozen guards who had witnessed your not-so-stealthy assassination, you could rather easily just stand your ground and counter every blow that came your way, systematically cutting down what felt like whole armies of enemies with little resistance.

However, your opponents no longer wait their turn to attack, and counter kills have been removed entirely. Squaring up against more than two foes can quickly work against you as you're beaten down by one offensive after another, and it's not until later in the release that you're equipped well enough to weather more than a few hits without getting skewered. Overall, it's a relatively dramatic change – especially if you're used to playing as an overpowered and ruthless killer, but it does make encounters arguably as intense as they should be.

Meanwhile, on your side of things, you're no longer able to switch between weapons on the fly. Your trusty hidden blade can't be used in direct combat any more, and you're limited strictly to one main armament at a time. Along with your gun of choice, you'll need to pick between three different types of melee weapons: one handed, heavy, and long. One handers are your usual swords, heavy arms tend to be two handed axes and claymores, while long weapons come in the form of spears, tridents, and javelins.

Each type has its own strengths and weaknesses as you'd expect, and finding your favourite loadout is an enjoyable process, but there's a definite lack of depth outside of the alterations to combat itself, which we suppose that, once again, reinforces the sense that stealth should come first. Having said that, the way that Unity appears to encourage you to form your own playstyle is in conflict with the need to do things quietly. For example, if you were to focus on melee combat in the hope that you could approach every situation like a machete-wielding madman, you'd soon realise that the majority of missions are designed to reward crafty players.

Again and again, Ubisoft has stressed that this newest instalment features 'blackbox' mission design, which essentially means that you're free to tackle objectives any way that you see fit, and to a degree, it's fulfilled its promise; unlike prior titles, you won't immediately fail a task if you don't stick to the strict guidelines. If you decide to wade into a building full of guards in broad daylight and attempt to fend off every single one of them before putting down your target, you can – but you'll miss out on a couple of bonus cutscenes if you don't follow the structure that's laid out for you.

It's still an undeniable step forward for a franchise that's never allowed the freedom of gameplay that it's always promised, though, and when it comes down to it, the release has some brilliant scenarios to sink your blade into. Coming up with your own plan of attack and then executing it while also adapting to some surprisingly dynamic situations captures what Assassin's Creed should have always been about, and it's here, along with its lovingly crafted game world, that Unity really comes into its own.

Ubisoft's latest isn't quite a revolution, then, but it does refine the formula in numerous ways, and we'd love to say that it's one of the best games in the series – except that we can't. Indeed, for all of its strengths, it's no secret that this is a technical abomination.

Capped at 30 frames-per-second, the release barely manages to hit that point on a regular basis. Instead, it sits at what feels like a constant 20-25FPS, particularly when you're mulling around large crowds of pedestrians. Paris is absolutely chocked full of people, and at times, it really feels like a living, breathing city – but while it's impressive to look down from a rooftop and see hundreds of peasants gathered in one place, we question whether the obvious strain it puts on the game's engine is worth it.

Walk into a crowd and you're immediately looking at a noticeable performance drop, and it gets even worse when some action kicks off. Get into a fight in a heavily populated location, and it can even become difficult to time your parries correctly because the title is chugging along so badly. As you can imagine, this leads to some severe bouts of frustration, especially since the release's load times are also abysmal.

If you fall in battle, you likely won't be too upset because of the competent checkpoint system that's in place, but then you'll remember how long it takes to boot up the game again. If you're lucky, you'll be staring at a load screen that lasts about twenty seconds – and if you're not, you'll be sitting twiddling your thumbs for a good minute or so. Taking a ridiculous amount of time to initially load your save file is one thing, but there's no excuse for such gigantic retry times. At the end of the day, you'll fear that dreadfully boring black screen more than the royal guards themselves.

And then there are the oh-so-infamous glitches. It's no exaggeration to say that you literally can't spend more than two minutes in Unity without seeing some sort of graphical cock-up – whether it's peasants clipping into walls or enemies falling through the floor during a fight. We've no doubt that most players will be able to look past these often comical encounters, but they occur at such a frequent rate that it becomes hard not to get incredibly annoyed, particularly if the game has managed to really capture your attention with an especially engaging mission just moments before you catch a glimpse of a man without a face. Goodbye, immersion.

These technical issues certainly aren't game breaking, but unbelievably, the worst is yet to come. Given the industry's recent obsession with always online releases, Unity is, of course, built on a framework that assumes that you're constantly connected to Ubisoft's servers. There are clan activities, dynamic co-op missions that appear in real time in your game world, and several smaller features that make it a typically 'social' experience. The only problem with this is that at the point of writing, the game can barely stay hooked up to its servers, and when it loses that vital connection, it has a horrible tendency to crash completely.

During our playthrough, the release froze on us a total of eight times, and each of these crashes was accompanied by a pop-up box that indicated that we had “lost connection to the Ubisoft servers”. We then had to manually shut down the software and restart it. As far as gaming sins go, software crashes are right up there with the very worst escort missions, and because Unity's problems seem tied to its publisher's increasingly pointless Uplay service, it makes the issue somewhat unforgivable.

Meanwhile, the title's aforementioned co-op component is actually quite good – at least, when it's running properly. At any time, you're free to invite friends or strangers to your game world, and from there you can freely roam the city or take on co-op based objectives. Dashing across rooftops with a pack of allies is empowering and effortlessly cool, and coordinating assassinations with your buddies is a real highlight when it all goes according to plan. It's a shame, then, that even the largely delightful co-op experience is marred by what is sometimes an even worse framerate, and glitch-ridden combat that sees you helplessly stuck in place as allies carry out flamboyant finishing moves on your foes.

Elsewhere, on the visual side of things, the next-gen exclusive stab-'em-up doesn't always look as pretty as it should. As we've come to expect from the series, it boasts a lovely art direction, but a terrible amount of pop-in sullies what is otherwise an attractive adventure – even if main character models, complete with some gorgeous clothing textures, look great throughout.

Conclusion

With Assassin's Creed Unity, there's a great game buried somewhere beneath an unforgivable amount of technical issues, from annoying glitches to frustrating crashes. It's a perfect example of how Ubisoft's insistence to annualise the series has backfired, as it's clearly an unfinished product. While it manages to both refine and add to the franchise's formula with enjoyable co-op, missions that encourage experimentation, and a few accessible RPG mechanics, we simply can't guarantee that your experience won't be plagued by problems both big and small.