'The Great Journey': Halo 2 turns 20 years old.

Halo: Combat Evolved, in no mean terms, revolutionised gaming as an art form. What started as a passion project by no more than 50 people in 1997 went on to become one of the biggest cultural phenomena of the 21st Century. As such, when development for a much-anticipated sequel fell into crisis, when release was delayed by over a year and 50% of content was cut, Bungie braced themselves for disaster. What they got, however, was a masterpiece.

The troubles and turmoil that struck Halo 2's development are well known among fans. Harsh deadlines, programmers sleeping in the office, divorces - it's no wonder Rolling Stone described the process as "hellish". So much was left on the cutting room floor that even the sequel's E3 demo looks wildly different from the Halo 2 we know and love today.

Nevertheless, they persisted, and upon it's eventual release in November 2004, Halo 2 was a smash hit. Selling 8 million copies, the shooter was the most popular game in Xbox history, and pioneered online gaming as we know it. It may be easy to say 20 years later, but the dedication of everyone at Bungie had paid off.

Halo 2's campaign takes the aliens you've spent the last game murdering with increasingly violent methods, and gives them character, identity and motivation. In fact, half of the single-player mode takes place through the eyes of The Arbiter, a warrior in the alien Covenant, as he slowly realises that the religion and empire he had dedicated his life to are nothing but genocidal lies. Don't get me wrong, you still get to do lots of murdering - it wouldn't be much of a shooter if you couldn't - but Halo 2's humanisation (well, they're aliens, but you know what I mean) of The Covenant stands to this day as one of the greatest pieces of worldbuilding in gaming history.

The parasitic, zombie-like Flood are back, and more horrifying than ever. We watch as 'High Charity' - The Covenant's holy city - is overrun and assimilated by just one Flood-controlled ship. "Gravemind" and "High Charity", the missions in question, are masterpieces in environmental storytelling. Each corridor we fight through seems more infected than the last, giving the player an impending sense of dread. While Halo Combat Evolved's Flood outbreak was eliminated at the game's outset, it's sequel ends with the parasite stronger than we've ever seen it - a terrifying thought.

While my mother's womb didn't come with a built-in Xbox Live connection, and as such I was unable to play Halo 2's multiplayer on launch, the game's multiplayer was just as groundbreaking as the one that came before it. Features such as party chat and custom matchmaking were revolutionised by Halo 2's multiplayer, and have been near-universal in every game since.

2014's remaster of Halo 2 did not spoil the feel of the game, unlike the anniversary edition of Halo CE. While Combat Evolved's "upgraded" graphics ruined the game's dark, gloomy atmosphere, 2's new graphics are nothing short of stunning.

The second installation of gaming's most iconic shooter wasn't without its flaws, just ask the development team (please don't - they'll probably start crying), but the fact that the game holds its own, and then some, two decades later speaks to it's triumphant brilliance. Created at a time where video gaming was still finding it's feet as an art from, Halo 2 not only laid the blueprints for the future, but was ahead of it's time.