Game Design

Core Loop

**4:00 AM. 'One more turn.'** Three hours have already passed. Civilization, Factorio, Stardew Valley - these games steal nights. But why? What makes players repeat the same action over and over, *and enjoy it*?

The answer is the **Core Loop**. It's the central cycle of actions a player repeats constantly. If the core loop is good - the game is addictive. If it's bad - the game is dead, no matter how much money was invested in graphics.

Цели урока

  • Understand the structure of a core loop: action → reward → upgrade
  • Analyze core loops of popular games
  • Distinguish between primary and secondary loops
  • See how loops create the 'one more turn' effect
  • Design simple core loops

Предварительные знания

  • What is a game: goals, rules, feedback
  • What Is a Game?

The core loop is what players pay for. Not the story, not the graphics - the feeling of progress in the cycle. Candy Crush made billions on the simplest loop: swipe → explosion → new candies. Understanding loops is the key to creating addictive (and, hopefully, ethical) products.

  • **Twitter/X**: scroll → interesting tweet → dopamine → more scrolling
  • **TikTok**: swipe → video → laugh/shock → more swiping
  • **Uber**: order → arrival → rating → readiness for the next order
  • **Email**: check → reply → inbox zero → sense of control
  • **Fitness trackers**: workout → stats → improvement → motivation for tomorrow

From arcade machines to mobile games

Space Invaders created the first perfect core loop: shoot → kill aliens → they speed up → shoot faster. Each cycle raises difficulty and tension. The machines ate coins because the loop was irresistible. This principle - escalating challenge - still works in every roguelike.

Anatomy of a Core Loop

Every core loop consists of three phases, looped into infinity:

**1. ACTION** - what the player *does*. Clicks, shoots, builds, swipes. This should be *enjoyable in itself* - tactile feedback, animation, sound.

**2. REWARD** - what the player *gets*. Points, coins, loot, unlock. The reward must be *meaningful* - have a use, move toward the goal.

**3. UPGRADE** - how the reward *amplifies* the next action. A new weapon, a character upgrade, unlocking a mechanic. This creates progression and a sense of growth.

Nested Loops: loops within loops

Good games have **multiple loops** of different durations. Short ones hold moment-to-moment engagement, long ones provide a long-term goal.

Each loop feeds the next. Micro-actions (taps) provide resources for session goals (upgrades), which drive meta-goals (Town Hall), which boost social status (clan wars).

Designing a good Loop

Not every loop works. Here are the rules that separate Diablo from forgotten clones:

**Instant feedback.** The action must *feel* immediate. Mario jumps with a 'boing', Diablo monsters explode. A 100ms delay kills satisfaction.

**Meaningful reward.** Not just '+10 XP', but concrete progress toward a goal. The player must *see* how the reward brings them closer to victory.

**Growing difficulty.** If the loop repeats identically - it's boring. Difficulty should grow alongside the player's power (see Flow State).

**Choice within the loop.** If every action is the same - it's a grind, not a game. There must be micro-decisions: which monster to attack, which upgrade to take.

**Anti-pattern: Hollow Loop.** There's action, there's reward - but the reward doesn't affect anything. Examples: meaningless achievements, currency with no use, points with no leaderboard. Such a loop is quickly exposed as 'running in place'.

Core Loop as Engagement Engine

What is the fundamental insight about Core Loop as Engagement Engine?

Core Loop in Diablo

Kill → Loot → Equip → Kill stronger monsters

**ACTION:** Kill monsters (satisfying effects, satisfying combat) **REWARD:** Loot drops - weapons, armor, gold **UPGRADE:** Equip the loot - become stronger **→ Now stronger monsters can be fought** Diablo has worked for 25+ years because this loop is *perfect*. Every kill leads to better gear. Every piece of gear leads to stronger monsters. An endless cycle.

In Cookie Clicker the core loop is: click → cookie → upgrade. Why is the game addictive even though the only action is clicking a cookie?

Cookie Clicker is deceptively simple. But upgrades work exponentially: first 1 cookie/click, then 10, then 1000, then millions. Numbers grow - the brain gets the signal of getting stronger. This is pure distilled progression without distractions.

Loops in Clash of Clans

From seconds to months

**Micro loop (seconds):** Tap a finished building → collect resources **Session loop (minutes):** Attack a base → get loot → train troops **Daily loop (hours):** Log in → collect daily rewards → start an upgrade **Meta loop (weeks):** Upgrade Town Hall → unlock new buildings and troops **Social loop (months):** Help the clan in war → get clan rewards → sense of belonging

Why is it hard to stop playing Civilization, even after hours of play?

The 'one more turn' effect: when a research finishes - a wonder is being built. When the wonder is built - a war ends. When the war ends - a new era begins. There's always *something* that's about to finish. You never stop at a 'neutral point'.

Упражнения

  1. Sketch the core loop for Tetris. What is the Action, Reward, and Upgrade? — Action: rotate and place a piece. Reward: a line disappears + points. Upgrade: ...here it's tricky - Tetris has no direct upgrade. Instead difficulty increases (speed). This is a 'negative upgrade' - challenge escalates. Tetris holds through escalation, not player empowerment.
  2. Spotify Wrapped (annual stats) - is it a loop? If so, describe it. Why do people share it on social media? — It's an annual meta-loop: listen to music → get Wrapped → share → receive social approval → listen more (to make the next Wrapped more interesting). People share because Wrapped creates identity signaling: 'my music reflects my personality'. Social reward + yearly anticipation = a powerful engagement hook.
  3. Design a core loop for an app that motivates drinking water. Describe Action, Reward, Upgrade, and how loops of different lengths support a long-term habit. — Micro-loop: tap 'drank a glass' → water-filling animation → sound of drops (instant feedback). Daily loop: filled daily goal → unlocked bottle customization (cosmetic reward). Weekly loop: 7-day streak → XP for avatar upgrade. Monthly loop: health stats + comparison with previous month. Social loop: league with friends competing on who drinks more. Upgrade: 'green' streaks give score multipliers - progress accelerates with habit consistency.

Core Loop in context

How the core loop connects to other game design concepts:

  • What is a game? — The core loop is the implementation of goals and feedback in a repeating structure
  • Feedback Loops — Positive and negative feedback modify the core loop
  • Progression — The upgrade part of the loop is the foundation of character progression
  • Flow State — A good loop balances challenge and skill

Итоги

  • **Core Loop** - the repeating cycle of Action → Reward → Upgrade, the heart of the game
  • Good games have **nested loops** of different durations (seconds → months)
  • The 'one more turn' effect arises when loops complete NOT in sync
  • Rules for a good loop: instant feedback, meaningful reward, growing difficulty
  • **Hollow Loop** - an anti-pattern: reward exists, but affects nothing

Вопросы для размышления

  • Consider a popular non-game app (a social network, messenger, or activity tracker). What is its core loop? What is the Action, Reward, Upgrade? How deliberately was this loop designed?

Связанные уроки

  • st-01-feedback-loops
Core Loop

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