Every game has a core mechanic that is used and performed by the players re-peatedly. In the book – Rules of Play, Salen and Zimmerman call this aspect of game design the core mechanic, but it is often also called the core loop. Core loops are essentially the extension of core mechanic, as the core mechanic can be some-thing as simple as moving a paddle in pong in such a way that it bounces the ball.
The core loop on the other hand could be the whole game of pong, where two players compete against one another trying to bounce the ball behind the other players paddle. The core loop is the repeatable foundation of games (Lovell, 2013).
By designing a core mechanic and a core loop around that, designers can create meaningful play and some form of pleasure. If a game isn’t particularly fun or pleasurable, it is most often fault of the core mechanic. (Salen & Zimmerman, 2003.)
Salen and Zimmerman also note that if the core mechanic is fun enough, then the player might not even care if they win or lose. They describe the phe-nomena same-but-different experience as a crucial part of players intentions to playing a game repeatedly. If the core mechanic is well designed, it allows for this same-but-different gameplay to emerge. Repeating the core mechanic should make it offer new variations to gameplay experience. This effect is occurring out-side the core mechanic when the player plays the game more than one time. Then the whole game should offer meaningful play and variation to the gameplay.
(Salen & Zimmerman, 2003.)
Core loop rarely is the complete game and most often it needs a retention game on top of it to make it pleasurable in any sense of time. In older games this could be something as simple as a highscore that you want to beat. (Lovell, 2013.) Figure 3 is Lovell’s 2013 explanation of a free-to-play game in a pyramid form.
On the bottom is the core loop, the foundation of the game. On top of that is the retention game, which keeps players interested in the core loop for a longer time, and on top of that is the almost optional superfan game. Superfan game, in lovells pyramid is the endgame that cater for big spenders, it often is highly competitive and social. This layer of the game is designed for players that regard the game as more of a hobby than a game. (Lovell, 2013.) The € symbols and Free tag in the core loop section represent the potential revenue generated with each part of the game in free-to-play games. Core loop needs to be free in order the game to function as a free-to-play game, but often the core loop can be designed in a way that makes progression faster with players spending money.
Figure 3. Free-to-play games. Lovell 2013.
The core loop should be in some ways pleasurable for all players and offer a natural end-point for players to leave the game and a reason for returning. (Luton, 2013.) Often free-to-play games have built in core loop that await player input, then reward the player for doing so and then a natural progression for players to return to the action phase (Figure 3) This progression is slated as upgrade in the Lutons core loop because they often are implemented as such. They are there to deepen the gameplay and making progression move visible and tangible. By adding waiting to this default core loop, there is insentive for players to leave and return to the game (Figure 4).
Figure 4. Basic core loop. Luton, 2013.
Figure 5. Basic core loop with waiting. Luton, 2013.
The core loop can also repeat multiple times within one play session. By imple-menting sessioning into the core loop, the developers can lengthen the lifespan of the game (Figure 5). Sessioning can be artificial in a sense that the core game-play loop cannot be continued without taking a break from the game. This is of-ten implemented to leave players wanting more and showing players when it is most suitable to stop playing. (Luton, 2013). An example of this can be seen in the commercially highly successful, Candy Crush Saga -game. In Candy Crush Saga, players cannot continue playing the game after a set number of failures on levels. Implementing sessioning and waiting into the core loop can be the best way to keep players interested in the game for a long time, as players are re-warded after a set period of time, (Luton, 2013.)
Figure 6. Core loop with sessioning. Luton, 2013.
Appointment mechanics often allow the player to decide when to return to the game when it is most suitable (Lovell, 2013.) Like in Clash Royale (Supercell, 2016) where the player can start opening different reward chests with varying wait times. The player in that game can plan when they want to return. Return triggers can also be tied to multiple different loops of actions that take different amount of time like in Gardenscapes the game informs when all hearts are re-plenished, but also when timed events are about to start or end. Lovell notes also that while this type of sessioning is almost always monetized they are there mostly for the retention game.