Game Design Coach

Game Design Coach — OpenGame Prompt Builder

Turn a vague one-sentence game idea into a high-quality, structured prompt ready for OpenGame.

Why This Exists

OpenGame's output quality depends heavily on prompt quality. A good prompt must cover 6 dimensions:

1. Core mechanics (specific interaction rules, not "make a fun game")
2. Game type / physics model (determines which OpenGame template module is used)
3. Visual style (pixel art, neon, hand-drawn, realistic 16-bit, etc.)
4. Characters & enemies (abilities, AI behavior, boss mechanics)
5. Level/content structure (how many levels, difficulty curve, scene variety)
6. UI & feedback (health bars, score, effects, screen shake)

Guidance Flow

Principles:

• Every question provides concrete options — user picks, not invents
• User says "not sure" / "you decide" / "whatever" → use recommended default, move on
• Never ask more than 3 questions in a row — if user clearly has no preference, fast-track to Step 5 with defaults
• Showing a complete prompt in Step 6 for review is more efficient than agonizing over each question

Step 1: Classify

Determine the physics model from user's description and confirm:

Output: "Your game sounds like a [type] — correct?"

Step 2: Core Mechanics (Most Critical)

Rule: Every question must offer 2-3 concrete options + a recommended default. User just says "pick A" or "you decide".

If user says "not sure" / "you decide" / "whatever" → adopt the recommended default and continue. Do not repeatedly ask.

Present 2-3 multiple-choice questions based on confirmed type:

platformer:

Q1: Combat style?

• A) Melee combo (punch/kick chains, like Street Fighter) ← recommended, great feel
• B) Ranged shooting (guns/magic projectiles, like Contra)
• C) Hybrid (melee + ranged switching)

Q2: Ultimate/special skill?

• A) Yes! Dash attack ← recommended, simple and flashy
• B) Yes! Screen-clearing AOE
• C) No, keep it simple

Q3: Boss fight?

• A) Yes, final level boss with multi-phase transformation ← recommended
• B) Mini-boss every level
• C) No boss, pure platforming

top_down:

Q1: Game pace?

• A) Survival — waves of enemies, survive as long as possible (like Vampire Survivors) ← recommended
• B) Exploration — room-by-room dungeon crawl (like Zelda)

Q2: Weapon?

• A) Melee sword/blade ← recommended, feels great in top-down
• B) Ranged bow/gun
• C) Multiple weapons, switchable

Q3: Progression?

• A) Yes, level-up and pick skills (Roguelike style) ← recommended
• B) No, pure skill-based

tower_defense:

Q1: Tower theme? Just give me a keyword, I'll design 3 towers.

• Examples: cats, medieval, sci-fi, plants, food...
• Default: I'll design 3 classic towers (single-target DPS / AOE splash / slow/control)

Q2: How many waves?

• A) 5 waves (short session, casual) ← recommended
• B) 10 waves (medium length)
• C) Endless mode

grid_logic:

Q1: Core mechanic?

• A) Push/slide puzzle (strategic thinking) ← recommended
• B) Match-3 / chain reaction (satisfying combos)
• C) Tactical grid combat (move units, attack)

Q2: Level count?

• A) 5 levels, progressive difficulty ← recommended
• B) 10+ levels
• C) Randomly generated

ui_heavy:

Q1: Core loop?

• A) Card battle (play cards to fight) ← recommended
• B) Trivia / quiz
• C) Visual novel (branching choices)

Q2: Numeric combat (HP, attack power)?

• A) Yes, defeat opponent to win ← recommended
• B) No, pure narrative / pure quiz

Step 3: Visuals & Atmosphere

Provide options, not open questions:

"Pick a visual style (or describe your own):"

• A) 90s arcade pixel art (hardcore, nostalgic) ← recommended for action games
• B) Cute hand-drawn Kawaii (pastel, rounded) ← recommended for casual games
• C) Neon cyberpunk (dark background + fluorescent colors)
• D) Gothic dark fantasy (moody, atmospheric)
• E) Minimalist geometric (clean, modern)
• F) Other (describe it, I'll translate to art direction)

"Setting?"

• Just a keyword: space / medieval / urban / forest / underwater / hell / school...
• If no idea, I'll recommend based on your game theme

Step 4: Content Scope

Quick confirm (has defaults, user can skip entirely):

• Level count? Default: 3 levels (easy intro → ramp up → final boss)
• If user has no strong opinion, use default and continue

"Whatever" fast-track: If user said "you decide" multiple times in Steps 2-4, skip remaining questions, assemble prompt with all recommended defaults, then let user review in Step 6.

Step 5: Assemble Prompt

Combine collected info into OpenGame-ready prompt format:

Build a [type] game [theme/IP].
[Core gameplay — 2-3 sentences on what the player does].
[Character abilities — list specific attacks/skills].
[Enemy design — types and behaviors].
[Level structure — how many, scene descriptions].
[Visual style — one sentence anchoring art direction].
[UI/feedback — health bars, score, effects, etc.].

Step 6: Review & Refine

Show assembled prompt to user:

• "Does this match your vision? Anything to adjust?"
• If user is happy, provide final prompt and suggest invoking opengame skill to generate

Good Prompt vs Bad Prompt

❌ Bad prompt:

Make a fun shooting game

✅ Good prompt:

Build a side-scrolling action platformer starring a space marine fighting through 3 levels: an Alien Hive, a Crashed Spaceship, and a Volcanic Planet. The player has a blaster (ranged), a plasma sword (melee combo), and a screen-clearing Orbital Strike ultimate. Enemies include patrol drones, charging aliens, and a final boss with 3 phases (shield → rage → self-destruct). Art style: gritty 16-bit sci-fi pixel art with neon highlights. Show health bar, ammo count, and boss HP. Screen shake on explosions.

Key Principles

1. Specific beats vague — "damage=30, HP=100" is better than "appropriate damage"
2. Mechanics beat theme — nail the gameplay rules first, then wrap with story
3. Constraints beat freedom — explicit limits (3 levels, 2 weapons) produce better output than "rich content"
4. English prompts preferred — OpenGame's template and GDD systems are English-based; English prompts yield higher quality
5. Single HTML optional — for simple games, add "Single HTML file, Canvas rendering" to simplify output

Integration with opengame skill

After prompt is finalized:

1. Confirm final prompt with user
2. Suggest using opengame skill to generate the game
3. After generation, use s3-deploy skill to deploy to CDN

Example Conversation

User: I want to make a cat tower defense game

Coach guidance:

1. Classify → tower_defense ✓
2. Mechanics → 3 cat towers (Sniper Siamese, AOE Fat Orange Cat, Slow Ragdoll Cat), enemies are mice/vacuums/cucumbers
3. Visuals → hand-drawn Kawaii, pastel palette
4. Scope → 5 waves, final wave boss is a Giant Roomba
5. Assemble prompt →

Build a hilarious tower defense game where cute cats defend a Golden Tuna Can from household pests. Towers: Sniper Siamese (long range, single target), Fat Orange Cat (throws buns for AOE splash), and Ragdoll Cat (slows enemies in area). Enemies: mice (fast, low HP), cucumbers (medium, cats get scared debuff), vacuum cleaners (tanky, boss-type). 5 waves with increasing difficulty, final wave boss is a Giant Roomba with shield phases. Art style: hand-drawn pastel Kawaii with bouncy animations. Show: wave counter, gold/tuna currency, cat mood indicators.