Linear is a word used to describe a games path of progression. Linear means the path does not branch - players go down a straight line, usually from level-to-level or map-to-map. Any of your actions will not change what you do next, meaning you have no option to where you'll go next. Some games may be partially linear due to side-quests. Gamers tend to prefer non-linear storyline and progression, but the linear style still has it's place. Real-time strategy games tend to favor linear advancement.