How your player characters progressively become more powerful in the game.
As player characters progress through a game, they typically gain new skills, abilities and more powerful equipment. The distribution of these gains throughout the game make up the power curve. Depending on how quickly or slowly you players progress, this will impact gameplay, a gamer’s perceived progression and desirable flow states.
Power curve design is a subject of some debate. Personally, I enjoy games with fast progression early on, while progression slows soon after. Others prefer slow progression while a player becomes familiarized with the game world, then faster progression, followed by slower progression in the later stages.
If your game has strong narrative elements, consider how power progression might impact important moments. Slowing progression during the climax of a story will help keep the focus on story elements over mechanics. The power curve is another opportunity for the game designer to influence gameplay and fun.