Halo 3 is less a sequel to Halo 2 than its direction continuation. Halo 2's development process was infamously torturous and Bungie had to push it out of the door before it was fully ready, leading to criticism of the game for being effectively incomplete on release. Halo 3 came out three years later on the more powerful X-Box 360 platform, allowing for a graphically more impressive game.
Thirteen years on from release, Halo 3 has finally made the transition to PC via The Master Chief Collection and it's a bit of a mixed bag. Being designed for more powerful hardware means the game consists of much larger environments and areas than the first two games, making it more fun to play with more sprawling combat areas. The game mixes up vehicle and in-person combat with more skill than the prior games and there's some stronger weapon design.
However, whilst both Halo and Halo 2 have been significant revised and updated over the years, Halo 3 has not, so whilst it looked far better than Halo 2 on release, it actually looks significantly worse than Halo 2: Anniversary, the version of the game that ships with The Master Chief Collection. This means there's a bit of an unexpected downgrade for people playing the series in order. Character models and textures are significantly less impressive than Halo 2, and the sudden dearth of fantastically-rendered CG movies in favour of far more clumsy, in-engine cut scenes is jarring.
Once you adjust to that, there's much to enjoy here with some solid redesign of enemies - the bullet-spongey Brutes from the second game have been improved and giving them their own, far more interesting weapons arsenal is a good move - and a storyline that twists and turns through several interesting spins. The re-focusing of the game on the Flood as the main enemy at the halfway point recalls the weaker moments of the first game and it can never quite get over that issue. Fighting intelligent enemies who know when to seek cover, use grenades and flank is is simply always going to be far more fun than fighting a bunch of Half-Life rejects who shuffle towards you in a straight line, veritably begging for you to shoot them. Level design also feels a bit stretched at the end of the game (including a nightmarish re-use of the infamous infinite identical rooms from the original game, thought fortunately very briefly, and a re-use of the same design for the final mission of the game).
A lot of these problems seem to be down to Halo 3 not really being supposed to exist. It was really the last act of Halo 2, but to make it work as a full game - albeit a 7-hour one that feels a little stingy after the 10 hours of the first two games - it's had a lot of filler added to it. Some of this filler is entertaining, but there are a few moments when you may find you grinding your teeth and wanting them to either come up with something more interesting or cut to the chase.
Halo 3 (***½) is an enjoyable first-person shooter which cannot match its forebear for its tighter design and stronger storytelling chops, and does resort to a few disappointing design decisions to drag its modest length out a bit longer. Still, it provides a solid conclusion to the original Halo trilogy. The game is available now on X-Box One and PC as part of The Master Chief Collection, which also includes remastered versions of Halo: Combat Evolved and Halo 2, and more moderately graphically-updated versions of Halo 3: ODST, Halo: Reach and Halo 4. A new Halo game, Halo Infinity, is due for release in 2021 on PC and X-Box Series X.