Chapter 25 — Further Reading

Progression design sits at the intersection of game feel, behavioral psychology, economic design, and level design. The reading list reflects that spread. Pick two or three to start with; add others as specific questions arise in your work.

Foundational Books on Game Design (with strong progression chapters)

Jesse Schell — The Art of Game Design: A Book of Lenses (3rd edition, 2019) Schell's "lenses" framework gives you specific interrogative tools for any design question. The lenses on reward, challenge, and the curve of interest apply directly to progression design. Chapters 17-21 cover motivation, interest curves, and progression pacing in depth. The single best general-purpose design book on my shelf, and the one I recommend most often to new designers. If you read only one book on your journey into game design, make it this one.

Ernest Adams and Joris Dormans — Game Mechanics: Advanced Game Design (2012) The book that formalized sources, sinks, converters, and traders as the primitives of economic design. Their framework scales from simple resource flow to progression-system modeling. The Machinations tool that accompanies the book lets you simulate progression curves and economic loops visually. Required reading if you are designing an RPG, ARPG, or any system with multiple interacting currencies.

Katie Salen and Eric Zimmerman — Rules of Play: Game Design Fundamentals (2003) The academic canon entry. Extensive coverage of game systems, emergent play, and the role of progression in player engagement. Drier than Schell, but thorough — worth dipping into for the conceptual rigor if not for the practitioner advice.

Tynan Sylvester — Designing Games: A Guide to Engineering Experiences (2013) Sylvester's book — he is the designer of RimWorld — covers progression through the lens of emergent experience. Particularly strong on how progression intersects with narrative and player investment. The chapter on "motivation and reward" is a useful complement to this textbook's coverage.

On Reward Psychology and Player Motivation

Jamie Madigan — Getting Gamers: The Psychology of Video Games and Their Impact on the People Who Play Them (2015) Madigan is the field's clearest writer on the psychology behind why progression systems work. Chapter 5 covers operant conditioning, variable-ratio schedules, and the specific psychological hooks that XP curves and loot drops exploit. If you want to understand why a well-tuned progression feels compelling — at the neurological and behavioral level — Madigan is the writer for you. His essay "The Psychology of Loot" is also freely available online and is a compact primer.

Nir Eyal — Hooked: How to Build Habit-Forming Products (2014) Not a game book, but the "Hook Model" (trigger, action, variable reward, investment) applies directly to progression design. Use with ethical care — the book is also a guide to what not to do if you care about player wellbeing, which Chapter 33 will take up. Worth reading to understand the full spectrum of what progression systems can do, including their exploitative extremes.

Edward Deci and Richard Ryan — Intrinsic Motivation and Self-Determination in Human Behavior (1985) The foundational text on self-determination theory (competence, autonomy, relatedness). Progression systems succeed when they support competence and autonomy; they fail when they substitute extrinsic rewards for intrinsic motivation. Dense academic psychology, but the framework is worth absorbing. The shorter Why We Do What We Do (Deci, 1995) is a more accessible summary.

Essays and Blog Posts

Daniel Cook — Lostgarden (various essays, 2003-present) Cook is one of the clearest thinkers on game-design theory writing today. His essays on skill chains, interest curves, and progression mechanics are required reading. Specific starters: "The Chemistry of Game Design," "Skill Chains," and "Short-Term and Long-Term Design Goals." Lostgarden.com archives most of them. Budget time — once you start, you will read for hours.

Clint Hocking — "Ludonarrative Dissonance in Bioshock" (2007) The essay that gave the field a vocabulary for when mechanical progression and narrative progression drift apart. Bioshock asks the player to make ethical choices while rewarding one ethical direction with more numerical power — creating a dissonance between what the game says and what the progression system teaches. The piece is short, widely-cited, and still the clearest single statement of why progression systems carry narrative implications whether you mean them to or not.

Raph Koster — A Theory of Fun for Game Design (2nd edition, 2013) Koster's short, illustrated book argues that fun is the act of learning — that progression systems are, at bottom, pacing devices for learning curves. The framework reframes progression away from reward-structure analysis toward skill-acquisition analysis. Short and provocative.

Sebastian Deterding — various academic papers on gamification Deterding has written extensively on progression systems in non-game contexts (gamification). His critiques of badly-applied XP systems in enterprise software double as a manual for what makes XP systems work in games — and what makes them fail. The paper "From Game Design Elements to Gamefulness" (2011, with co-authors) is the usual starting point.

GDC and Conference Talks

"The Design of Diablo III: Reaper of Souls" — Josh Mosqueira, Kevin Martens, Travis Day (GDC 2014) The Blizzard team's public postmortem on the Loot 2.0 and Reaper of Souls redesigns covered in Case Study 25.2. Available on the GDC Vault (free portion includes overview). Watch alongside the case study for the designers' own framing of the reset.

"Saving Diablo III: The Story of Loot 2.0" — Travis Day (various interviews) Day gave several interview-format talks on the Loot 2.0 specifics after RoS shipped. Worth searching YouTube and gaming podcasts. The central lesson he repeats: "Legendary should mean legendary."

"The Design of Hollow Knight" — Team Cherry (various talks, interviews) Team Cherry gave relatively few formal talks, but several interviews and "No Clip" documentary coverage discuss the charm system's design process. The charm system did not ship in its final form — it was extensively playtested and retuned. Their commentary is instructive on small-team iteration.

"Path of Exile: Designing Permanent Leagues" — Chris Wilson (GDC 2019) Wilson (co-founder, Grinding Gear Games) explains how Path of Exile's league system handles progression across years of content. The talk covers power-creep management, seasonal resets, and how horizontal progression gets integrated with vertical. Essential for anyone designing live-service progression.

"Metroidvania Design: Using Space as Progression" — various speakers A recurring GDC topic covering unlock-based progression. Talks from Tom Happ (Axiom Verge), Moon Studios (Ori), and various Metroid-franchise developers are particularly useful. Use the GDC Vault search.

"Balancing Character Progression in Action RPGs" — Diablo/PoE/Last Epoch retrospectives Multiple talks over the years have covered the numerical tuning of progression systems in the ARPG space. Recent talks include postmortems from Eleventh Hour Games (Last Epoch) and from Diablo IV team members on the shift from D3's structure.

Video Essays and YouTube

Mark Brown — Game Maker's Toolkit GMT's episodes on progression include "How Games Use Feedback Loops," "What Makes a Good Metroidvania," and multiple analyses of specific games' progression systems. Brown is the best contemporary video essayist on game design mechanics; his videos are always well-researched and often include designer interviews.

Jacob Geller — cultural criticism on games Geller's essays touch on progression indirectly. His videos on Elden Ring, Hollow Knight, and the "souls genre" cover how progression systems shape narrative experience.

Razbuten — player-psychology playthroughs Razbuten runs experiments (playing games blind, playing with non-gamer family members) that reveal how progression systems feel to players who have not internalized genre conventions. Eye-opening for designers who have played too many games to remember what fresh players experience.

Joseph Anderson — long-form game analysis Anderson's hour-plus video essays on specific games often dive into progression-system analysis. His essays on Hollow Knight, Bloodborne, and Dark Souls are useful for thinking about skill-vs-power ratios in practice.

Noclip — documentary series Several Noclip documentaries include substantial interviews with designers about their progression systems. The Hollow Knight documentary, the Path of Exile series, and the Diablo III retrospective (if available) all contain insights not found elsewhere.

Games to Study for Progression Craft

Hollow Knight — Case Study 25.1. The charm system, the notch limit, and the unlock-based Metroidvania progression. Play once without guides. Note which loadouts you gravitate to, which you resist. Then read community build guides and see how much wider the option space is than you realized.

Diablo III: Reaper of Souls — Case Study 25.2. Play the current (post-RoS) version, then look up the 2012 launch reviews. The gap between the two games is the case study distilled.

Path of Exile — The extreme of web-style progression. Start a character, reach mapping (endgame), and observe the progression texture. Expect to consult external build resources; the game is designed that way. Compare with your prior instincts about "tutorials should teach everything" — PoE teaches nothing about its tree and is beloved anyway. Why?

Final Fantasy X — The sphere grid. Unique, rarely imitated, and worth studying once to understand what spatial progression systems feel like. The late-game grid-breaking (sending any character to any position) is a deliberate design choice; note what it gains and what it costs.

Ori and the Will of the Wisps — Modern Metroidvania progression at its most polished. Tighter than Hollow Knight, more forgiving, more narratively-integrated. Study the pacing of ability acquisition especially — Ori's movement upgrades land with a cadence that Hollow Knight can feel slow against.

World of Warcraft (any era) — The long history of MMO progression, including multiple power-creep responses. Play the free starting experience (currently Dragonflight era) for 10-20 hours; then read retrospectives on Vanilla WoW's brutal 1-60 grind. The comparison is the progression-design history of a generation.

Dark Souls III or Elden Ring — FromSoftware's approach to progression: modest character-power growth, enormous player-skill growth, spatial unlock via boss kills. Study the stat soft-caps at 40/60 and how the game encourages specialization without enforcing it.

Celeste — Near-zero character progression, enormous player-skill progression. Play to the end. Observe how the game produces the feeling of progression without any of the traditional progression apparatus. The chapter's reference point for "mastery is progression, even without numbers."

Hearthstone or Magic: The Gathering — TCGs with Standard rotation. Study how rotation manages power creep over years of content releases. Play a season from launch to expansion rotation if you can; feel the shift.

Last Epoch — A contemporary ARPG that explicitly designs around the lessons of D3's reset. Passive trees, mastery classes, unique items with legendary effects, and a carefully-tuned difficulty ladder. Strong teaching game for modern ARPG progression.

Tools and Resources

Machinations (machinations.io) — Joris Dormans's economic modeling tool. Build progression-system models visually, simulate resource flows, catch balance problems before they ship. Free for non-commercial use. Paid tiers for studios.

AnyDice or Troll Dice (online probability calculators) — For simulating loot drop probabilities, critical hit chains, and other random-elements of progression. Useful when tuning drop rates or evaluating the expected value of a loot pool.

Spreadsheet tools (Excel, Google Sheets) — The humblest progression-design tool, and still the most used. Build your XP curve in a sheet, plot it, compute cumulative totals, estimate time-to-cap. Most professional RPG balance work happens in spreadsheets before it touches code.

Godot's AnimationPlayer, Timer, and Signal system — For implementing the progression code from this chapter. The Godot documentation on signals and Autoload singletons is worth reading in depth before building production-grade progression systems.

Unity's ScriptableObject system — If you work in Unity rather than Godot, ScriptableObjects are the standard pattern for authoring skill trees, ability definitions, and progression data as editable assets.

Academic Perspectives

Mia Consalvo — Cheating: Gaining Advantage in Videogames (2007) On how players optimize and exploit progression systems. The "cheating" framing is provocative — Consalvo argues that min-maxing is a form of cheating, and that designers should understand it as such. Worth engaging with whether you agree or not.

T.L. Taylor — Play Between Worlds (2006) Ethnography of EverQuest players. Dated but illuminating on how long-grind progression systems shape player community and identity. The lessons transfer to modern live-service games.

Nick Yee — The Proteus Paradox (2014) Yee's research on MMO player motivation (achievement, social, immersion axes) informs progression-system design. His "gamer motivation model" is widely used in AAA studio research departments.

Where to Go Next

This chapter's progression system is the scaffolding. Chapter 26 puts it under load: combat design, where hit points, damage scaling, ability interactions, and enemy tuning all intersect with the numbers you just specified. Expect to re-tune progression once combat is built — the two systems validate or break each other.

Chapter 32 (Game Balancing) returns to progression with tools for systematic balance work. If Chapter 25 is about shape, Chapter 32 is about fit — getting the numbers right across the full content arc.

Chapter 33 (Game Design Ethics) takes up the darker applications of progression systems — grinding, exploitation, dark patterns in free-to-play — and asks when your progression system crosses from engagement into manipulation. Reading 33 will change how you design the systems 25 introduced. Plan for it.

For preparation, play one game whose progression is famously compelling to you personally — whatever that game is — and then replay it trying to articulate specifically why each progression decision lands. Notice the shape of the curve, the branching of the tree, the caps, the unlock pacing, the creep policy. Write down what you notice. The articulation is the practice. The practice is how you get better.

Then turn the page.