A game tester is not a person who plays games all the day and gets money for that. In the game industry, QA is the way to ensure a proper quality of gameplay and to avoid bugs that affect playing experience. Game testing can be a real challenge, especially in case of test automation. Be it mobile, online or computer game, testing is an inevitable part of game development.
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.