RuneScore is a points system used to measure completed achievements. It was added on 29 August 2017 and can be viewed in the hero tab. Each achievement has an assigned value and upon completing the achievement its value is added to the player's RuneScore.
The maximum possible RuneScore is currently 18,420. Some achievements which are heavily dependent on luck, such as boss pets or boss collection log achievements, do not contribute to a player's RuneScore.