The games industry often struggles with difficulty curves, as developers aim to maintain challenge without frustrating players. Russell Kay, creator of lemmings, emphasizes smoothing curves by grouping mechanics and avoiding abrupt changes. New mechanics—like enemies, abilities, or rules—should be introduced gradually to keep players engaged. Kay argues against the myth that games must continually escalate difficulty, instead focusing on giving players a sense of progression.

Smoothing involves removing extreme variances in difficulty and assigning individual curves to mechanics. Techniques include optional collectibles, dynamic adjustment, and multiple learning paths. Visual and contextual hints (e.g., highlighted jump points in Mario) help players without overwhelming them. Avoiding penalties for failure and hiding core mechanics are critical.

Data-driven adjustments are key. Analyzing death clusters or level completion rates reveals where curves are too steep. For example, if 80% complete level 4 but only 20% finish level 5, the latter is likely too hard. Kay advocates targeting specific player groups rather than trying to satisfy everyone, as each game’s curve must align with its audience’s expectations.