Levels

In games there is usually a menu that allows the player to choose what level they are going to play, this then allow players to choose the level they want to play, usually they still have to go through the process of unlocking the levels.

A simple system is; play level 1 and the completion is rewarded with level 2. this carries on so on until the end of the game, but the player has the chance to repeat the previous level by going back on the menu and selecting it. A lot of games break down the total amount of levels into sections or chapters. Games that involve lots of different levels specially in the puzzle category have lots of different levels and usually are broken down in to either level difficulty or chapters in which then players can choose were they want to begin.

Angry Birds use an interesting Chapter method with each new chapter being harder but also having a change of environment and assets. Screen shot: