[2021] Just purchased and downloaded fall guys however I’m unable to play it and getting this message

Try verifying your game files. I... pressed enter too early:

Launch Steam

From the Library section, right-click on the game and select Properties from the menu.

Select the Local files tab and click the Verify integrity of game files... button.

Steam will verify the game's files - this process may take several minutes.

This can often sort a lot of pop-ups - let me know if it works!