In action-RPG titles such as Diablo or Guild Wars, the gameplay is built on the growth of the character's strength. This is carried out by a system of experience and levels associated with a system of equipment. To reach the next level the player has to cumulate enough points of experience. By passing through a succession of challenges, he will obtain this experience as well as the equipment needed for the next challenge.
Even though this system looks ideal and scalable, it has its weaknesses. When the limit of progression is reached, the game looses its interest and the motivation disappears. If there is no limit, the system does not offer any objectives or references and thus the motivation is very weak.
In the case of Diablo, the randomness of categories and reward characteristics increases the motivation of players to replay in order to achieve the perfect item. The disadvantage is that the player has no real reference of the ratio challenge / reward since one “unique” item can be the reward for next to no challenge.