It probably sounds kind of cool: "I work as a game tester". But it's one of the most challenging area of gamemaking.
Projects
In our games, the tester does everything to make the product better.
Processes
Our QA engineers control everything in the testing process - including the logic of the story, literacy, and the mutual arrangement of elements.
You need to be able to put yourself in the player's shoes as you work
Why is this important? Simply because, by testing the workability of the quests, the ability to go through the entire gameplay unmistakably and consistently, you'll never get to the non-linear moments of the game, which often violate reasonable rational logic.