Even 100% code coverage does not guarantee that your software is perfect. But code coverage metrics can help to optimize QA process, thus, save project budget. It is measured according to several levels like fucntion, statement, decision, condition (MC/DC & MCC), et.
What does it take for a game to succeed in 2020? What helps product owners save money and users be satisfied with the game? The better is your testing, the higher the quality of your game will be. So, proper testing is key to turn good games into great ones.