Halo SPV3—Singleplayer Version 3—is a total overhaul mod that brings new levels, weapons, enemies, graphics, and other updates and new features to the aged FPS Halo: Combat Evolved. Originally released in August 2017, a new version called SPV3.2 went live over the weekend that adds six new missions, a new launcher and update system, and support for 4K graphics and ultrawide resolutions.
SPV3.2 weighs in at a little over 3.5GB, and obviously you'll need to have a legitimate copy of Halo on PC at hand too. Also required, for anyone not running Windows 10, is .NET 4.6.1, and the developers recommend that you install the mod to the recommended location, "or at the very least NOT in Program Files, and NOT on top of HCE or an older version of SPV3." You'll need to set scaling in your Windows display settings to 100 percent, and it probably wouldn't hurt to deactivate your antivirus software to avoid false positives popping during the install process.
It may not be the simplest and most intuitive installation process, but that's life with big mods, and the vastly improved visual quality and effects speak for themselves. Some users are reporting glitches and bugs in the SPV3.2 subreddit (again, life with mods) but overall the response seems very positive.
Halo SPV3.2 will be rendered largely redundant when Halo: The Master Chief Collection comes to PC, at least when it comes to playing the original campaign, but aside from a vague "later this year," we have no idea when that will be. Until it happens (and don't forget, MCC is releasing chronologically, so Reach will be out before Combat Evolved), SPV3.2 sounds like a must-have for anyone looking to scratch a Halo itch.