If downloaded via GOG Galaxy your profile.json ought to transfer. Failing that it's relatively simple with the baked in debug panel to restore progress. Skip to section 9 in this document (
https://steamcommunity.com/sharedfiles/filedetails/?id=2464626495and ctrl + F to "RESTORING PROGRESS") or I suppose I can just copy paste it in here.
RESTORING PROGRESS
By fully restoring the game, it is possible that you will lose all saved progress. Here are a few ways to quickly return to what you once had via the debug panel:
EASY MONEY
When Brigador is running, press F1 on your keyboard to open the debug panel, and left click on the MONEY DEBUG tab.
The money slider allows you to adjust the amount of money the player has in the bank. Normally, this slider will only have a range from zero to ten million. Press Ctrl + Left Click on the slider, and you will be able manually enter any value you require.
Press F1 again to close the debug panel.
QUICK COMPLETION
If you have lost progress in CAMPAIGN mode, when Brigador is running, press F1 on your keyboard to open the debug panel and left click on the MAIN tab.
Check the first box marked “devmode” and then press F1 again on your keyboard to close the debug panel.
With devmode enabled, new keybinds become available. Press Home on your keyboard when in a level to instantly win that mission and be taken to the results screen. The game will mark you off as having completed that CAMPAIGN mission (N.B. Please make sure that the devmode-only UNLOCKS option is still set to ENABLED in SETTINGS > GENERAL).
Press F1 again and turn off devmode once you have reached the point you require - devmode actively blocks the game from sending achievement information to Steam, so you will not earn any Steam achievements when devmode is active.
ACCESS EVERYTHING
If you wish to access all the game’s content, when Brigador is running, press F1 on your keyboard to open the debug panel and left click on the MAIN tab.
Check the first box marked “devmode” and then press F1 again on your keyboard to close the debug panel.
On the main menu of Brigador, click SETTINGS and scroll down to the bottom of GENERAL - you will see a new option marked UNLOCKS.
Left click to set UNLOCKS to disabled. All content in the game is now accessible from the menus - this means you are free to try any campaign mission, read any lore entry and try any operation and loadout in FREELANCE mode.
Disabled unlocks are only available when devmode is active. Turning off devmode will return the game to the state it was before you disabled UNLOCKS. You will not earn any achievements when devmode is active.
