At long last, Halo: Reach has finally come to PC and Xbox One. If you're never experienced Noble Team's dramatic sacrifice, now is a great time to jump in. Everything isn't 100% perfect with this port, but with the game available on modern platforms (not to mention for the first time on PC), it's bound to only get better from here.
Halo is primarily known for its multiplayer suite, but Reach does feature one of the better campaigns in the series' history. A dark, somber tone, downbeat music, and some excellent level design punctuate what is a thrilling and emotional journey to save humanity. It was a touching send-off for original developer Bungie back in 2010, but it's still worth experiencing in 2019 for those in love with the Halo brand.
How much time will you need to set aside to finish it, though? Well, that depends on a lot of different factors. Like with many shooters, skill plays a big role. If you're able to land consistent headshots and conserve ammo, Reach won't be that long. From my personal experience of being relatively good at FPS games, I finished the campaign by myself on Legendary difficulty in nine and a half hours.
One caveat I need to mention is that I originally did the same feat on Xbox 360 back in 2010. While I haven't revisited the campaign in nine years, I remembered bits and pieces of certain choke points that stopped me. I'm also not unfamiliar with a mouse and keyboard, preferring to play most games on PC. That experience helped immensely.
If you're brand new to Reach, though–and not playing on the hardest setting–your time will vary between seven and 10 hours. The cutscenes amount to around 90 minutes, so you can add that on top of the quoted time. With the campaign being made up of only 10 playable levels, it's not very drawn out or repetitive (apart from every scenario being "shoot these guys").
If that sounds short, there are a few incentives to return to campaign levels. Xbox Live achievements will have you chasing par scores and times on every level and there are a series of miscellaneous achievements for specific missions. These can amount to "find some random item" or "make sure X vehicle doesn't explode." It's not crazy in-depth, but it's at least something extra on top of simply finishing each level.
You can even tinker with the "Skulls" system that Halo has offered since Halo 2. These are modifiers for combat that can toughen the enemies, improve your abilities, or generally alter the game in cosmetic manners. It may not be the most enthralling way to replay levels, but it does allow players to customize their playthrough however they see fit.
You also can't ignore the multiplayer portion, but that goes beyond the scope of this post. For all intents and purposes, Reach offers an old-school campaign that won't eat up endless hours. There are ways to stretch it out, but the onus is on the player to do so.