Checkpoint helps your program get back to where it was by providing checkpoints to continue from, combine this with some intelligent "where were we" logic at the start of each checkpoint and saving of essential data to disk (functionality not provided by Checkpoint) and your program will be able to continue as if the world didn't stop existing 😕.
If you want to play arround and learn how to use Checkpoint then download the repo and run demo.lua in you CC computer. Feel free to play around with the demo flags.
https://squiddev-cc.github.io/howl.ci/?p=travis%2Fbuilds&repo=CC-Hive%2FCheckpoint