Changelog
Here's the changelog for the latest test build available right now on the test branch (check out the next chapter to try it).
New content/features
- Added the "Sandbox" and "Permadeath" difficulties
- Added difficulty specific campaign achievements
Improvements
- Resetting campaign doesn't change the agent names and skins anymore (but still resets the skills)
- Improved the perk buttons
Fixes
- Fixed invisible character in the setup scene when they are in an upper storey
- Fixed visual glitches sometimes happening after changing the skin and/or loadout of a character
Reminder: switching to the test branch
In the Steam client, right-click on the game from your library and select "Properties".
Select the "BETAS" tab.
Select the "test" branch listed in the dropdown menu under "Select the beta you would like to opt into".

The game then should automatically update to the test version.
To switch back to the public branch, just select "None" in the betas dropdown.
Changed depots in test branch