So a bit of background; the first time I opened the game and started playing I received no achievements. The second time I idled in the menu and got 265/1500 achievements after which nothing. I uninstalled the saved files in the Steam folder as instructed, reinstalled, and waited 10 hours, but nothing. I reinstalled it again, but nothing.

Finally, I went into the registry editor on the latest Windows operating system, started searching for entries with RollingBall, and found the cache. (Notice there are plenty more entries but you only have to delete the one referred to here)

These instructions incorporate the information gathered from other players in the discussions section of the game. Thank you all who have been active in this respect.

What to do:

1. Find RollingBall in your Steam library (app) - right click - browse local files - Ctrl + A - Delete.

2. Uninstall RollingBall in your Steam library (app).

3. Open Registry Editor - find the following MuiCache (\Software\Classes\Local Settings\Software\Microsoft\Windows\Shell\MuiCache)

4. Select: C:\Program Files (x86)\Steam\steamapps\common\RollingBall Unlimited World\RollingBall_UW\Binaries\Win32\RollingBall_UW.exe.ApplicationCompany / REG_SZ / Epic_Games, Inc.

5. Delete the selected entry.

6. Install and open the game and idle until all achievements pop up. It might take a few seconds before they start showing.

Result: You should be able to get all the achievements within 30 minutes of idling. There is no 5-second rule unlike what the Dev might have stated previously as I was able to receive one achievement after the other.

I hope this helps. Enjoy your achievements!