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
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
- 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.
- 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.
- 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?