The Master Chief’s iconic journey includes six games, built for PC and collected in a single integrated experience. Whether you’re a long-time fan or meeting Spartan 117 for the first time, The Master Chief Collection is the definitive Halo gaming experience.
MCC is on sale during the Steam Summer Sale, at 75% off until July 13th. Can't recommend it enough!
If anyone is still on the fence, this is the time to give it a try. I'm biased for obvious reasons, but the community support and new workshop content getting made is probably my favorite part of this collection. It's just pure, microtransaction-free fun and a blast from the past
It's 170GB if you download all the games at once, and even then the majority of that is from Halo 2 Anniversary. You can pick and choose which games to download and not download (e.g. you can download Halo CE campaign and Halo 3 multiplayer, but not anything else).