Do you ever wanted to save your world state (like coordinates, health etc) and then return to the previous state later? I am sure you wanted, so congratulations! This mod solves that problem.

Note: this mod is in very early stage. It can destroy your world. This mod also potentially can be used to duplicate items, so the only purpose of this mod is to have fun.
This mod was written with GameTest Framework, and you need to enable it in your world settings.

Some gameplay:

What already implemented:
1) Blocks revert (not for all blocks)
2) Mobs and Players positions revert
3) Mobs and Players health revert
4) Weather revert
5) Daytime revert

What's left:
1) Inventory & Chests revert
2) Hunger revert
3) Reverting killed and spawned mobs

Note: you can only revert checkpoint once

You can get spawnpoint items from the creative inventory

1. Download the addon itself
2. Open the file
3. Apply behavior and resource packs in map settings
4. Enable GameTest Framework option in world settings