I recently made a program that will allow you to force checkpoints during the campaign of the Halo games on PC. It includes the MCC, the original CE PC port, Custom Edition, and Halo 2 Vista. I know there's a checkpoint manager that already exists, but I wanted to make something simpler and also wanted to learn more about programming something that plays around with memory. I will post a GitHub link below. Please let me know if you run into any issues with it!

Please also make sure you disable any relevant anti-cheat software before using it.

https://github.com/Jestzer/Force.Halo.Checkpoints