Well, thank goodness for that. After a superb behind closed-doors showing at E3 2014, Rainbow Six Siege, via two poor betas and many, many increasingly silly trailers, looked like it might have been Ubisofted to the nines - stupidly-named characters, perks, pre-order nonsense, towers? - and essentially ruined. That, amazingly, hasn't happened, and instead we've got one of the best team-based tactical shooters in years.

The core of Siege's success is how it is simple without being simplistic, its main systems easy to learn but flexible enough to embrace creative strategy. Both teams, each made up of five players, take turns attacking and defending an objective (a hostage, a bomb, etc). Rounds are short by default and shorter still if you make the wrong move. Play is split between two phases: a short planning section where you use drones to scope out strongholds or barricade your choke points, followed by the action phase. A large chunk of the environment can be demolished, breached, or altered to give you an advantage. First team to three wins, wins.

This setup is easy to 'get', and the way in which it gets players into (and through) games is Siege's main appeal. But what makes it so special is the way the game fosters inherent teamwork through its classes and their abilities, meaning even those without a mic can instantly know which teammate they need to be pairing up with, and act accordingly. Most of the attacking team's perks are based around breaching and covering advances: the defending squad's abilities are about upping max health, reviving players from range, booby-trapping doors, or protecting against grenade barrages.

Siege only enables one of each specialised class per team, so you'll often have to switch to your second or third favourite operator (if you have them unlocked), meaning players are encouraged to stretch themselves, rather than constantly picking Fuze. It's reminiscent, in a way, of the original Left 4 Dead's Versus mode: each of the infected in that game had a role, and making their various attributes work in concert was the key to success. Siege is exactly the same, despite the two games' obvious differences: they're both intuitive, while encouraging grand plans. The constant repetition of rounds - and the switching of roles - spur players on to do better next time, while also giving both teams insight into the other's playstyle. Adapting to your opponent, working out how they move, where they set up, and how they fight, gives Siege a cerebral thrill not often found.

The game seems small: small maps, small rounds, small teams, but like everything else here it's a malleable framework, to be shaped and exploited. Tight time limits don't mean you have to rush - in fact the other team often gets jumpy if you don't try and storm in immediately. Having small teams doesn't mean that they can't be broken down still further, into two main squads with one lookout - huddled players are easily dealt with. And small maps may mean fewer rooms, but it doesn't mean less choice. Siege scales to how you play: a successful assault can make you feel like you're leading a charge of twenty soldiers, sound and fury erupting as you enter rooms and kill hostage takers. But mistime an assault and suddenly it all feels very lonely.

Some will moan that this new Rainbow Six isn't Rainbow Six enough, of course, but then those people are mainly interested in planning phases that feature more lustful panting over blueprints than the average series of Grand fucking Designs. There's a depth here that slowly reveals itself, a wealth of strategic choices that come about through repeat play. One of the most arresting examples of this is players learning to use sound as a lure, or as misdirection: in early games there'll be a lot of charging about, but Siege's audio work is so good you'll often learn to hear foes before you see them, meaning good teams will quickly try and dampen their signatures. Like most things in the game, the audio design's initial use can be adapted, controlled, adjusted: a bang on the wall here, a deliberately heavy footstep there, each a setup to turn teams away from your true intentions.

Other tactics are less involved, but just as satisfying: dead teammates using CCTV cameras to tag enemies, walls breached to throw dust and smoke while you swing in through a window, hostage rooms left deliberately unguarded as traps. Smaller maps have obvious focal points, but larger ones like a snow-covered chalet with a grand hall and a library make for larger, tenser games of cat and mouse. There are twitch moments, but Siege isn't a twitch shooter: your weapon is the thing you should use last, not first.

Which is a good thing, because the shooting - while serviceable - isn't the greatest, lacking punch or intensity, and sometimes falling prey to shoddy hit detection. For the most part it feels responsive and satisfying - especially in casual games - but it can also feel like you should (or shouldn't) have been killed in one-on-ones. The killcam is little better, telling more half-truths and outright lies than a sports star on a chat show. Rainbow Six Siege feels like a game built with esports ambitions, but at the moment its netcode, shooting, or both aren't strong enough for it to get to that level.

Troublesome too is the use of microtransactions in a full-price game, in the form of boosters which award more 'renown' (XP), which is spent on operators and weapon upgrades. It rankles to boot the game and see the 'shop' icon there, and while it's not pay to win at the moment, it feels a little too in your face, a little too easy to see it and get yourself a boost. This is, of course, the point, but in a game supposedly all about balance it doesn't sit right. And the less said about Terrorist Hunt on consoles, the better: what is a great game of bomb defusal PvE (with tables turning midway through in L4D-alike crescendo moments where the AI swarms you) is rendered near unplayable thanks to the frame rate halving from 60 online to 30. Locking to 30 is one thing, but being able to play it at double in one mode and then having to switch down jars spectacularly.

Rainbow Six Siege is built, however, to be played online, and it delivers. A shooter housed inside a strategy game, it's both a great instalment in a famous, if fading, franchise as well as something that can stand on its own.

Version Tested: PS4