Experience levels and badges are used for gamification purposes. Their goal is to pull you into a game to help achieve your goals.
There are five experience levels. The more you practice and the more correct answers you have, the higher your experience level will be.
Additionally, there are nine badges, and you must meet certain conditions to earn them. For example, to get a “Winning Run” badge, you must complete five tests in a row with a score higher than 90%.