How to fix common bugs in AI-made games

Use it for: classic tower defense with a fixed route and placed towers. The most reliable starting point for the genre.

Variables

Master prompt

Make a one-screen 2D tower defense game set in a {{theme}}.
PATH: {{enemy}} walk a fixed path through {{waypoints}} to {{base}}. Draw the path clearly. Enemies move from waypoint to waypoint and never leave the path.
BUILDING: The player clicks or taps an empty build tile beside the path to open a small menu of towers:
- {{tower_1}}
- {{tower_2}}
- {{tower_3}}
Greyed-out buttons when unaffordable. Tapping a built tower shows its range circle and a Sell button (refund 50%).
ECONOMY: Start with {{start_money}} coins. Each enemy defeated gives {{reward}} coins with a floating "+{{reward}}".
WIN/LOSE: {{base}} has {{lives}} lives; each enemy that reaches it costs 1. Survive {{waves}} waves to win.
WAVES: Waves start with a Start Wave button. Use a wave list: each wave adds enemies and +10% enemy health; every 4th wave adds a faster enemy type; the last wave has a boss with a health bar.
FEEDBACK: Enemies flash white when hit, pop into particles when defeated, and the screen shakes briefly when a life is lost.
HUD: coins, lives and wave number at the top; Start Wave and Pause buttons.
STYLE: {{palette}}, simple shapes drawn in code, no external images.
CONSTRAINTS: one HTML file, works with mouse and touch, all movement based on elapsed time, Restart button on the win and lose screens.

Worked example

Make a one-screen 2D tower defense game set in a backyard garden. PATH: slugs walk a fixed path through 6 waypoints snaking from the left edge to the garden gate on the right… Towers: Sprinkler, 10 coins, slows enemies 40% in range; Pea Shooter, 25 coins, single target; Bee Hive, 40 coins, small area damage. Start with 100 coins, 5 per slug. 10 lives, 12 waves. Flat bright greens and browns…

After the first generation, check: enemies stay on the path; towers only fire within the drawn range; selling refunds the right amount; the boss appears on the last wave.

Strong follow-ups

• "Add a 2x speed button. Don't change anything else."
• "Add upgrades: tap a tower to upgrade to level 2 (+50% damage) for 1.5x its price."

Use it for: any subject quiz you'll reuse with new questions every week.

Variables

Master prompt

Make a quiz game for {{subject}}.
DATA: put all questions in an editable array at the very top of the code, clearly labelled QUESTIONS. Each item: question, four answers, index of the correct answer, optional explanation. Use exactly these questions:
{{questions}}
FLOW: shuffle questions and answer order; never repeat within a game. One question at a time with four large buttons (keys 1-4 also work).
TIMER: {{timer}}.
TEAMS: {{teams}}. If teams: show whose turn it is; correct = +10 to that team; turns rotate each question.
FEEDBACK: correct: {{reward}}. Wrong or timeout: chosen answer red, correct answer green, explanation shown for 3 seconds.
END: scoreboard, list of missed questions with correct answers, Play Again.
DESIGN: high contrast, at least 28 px answer text, readable on a projector and a phone.
CONSTRAINTS: one HTML file, works offline, no external fonts or images.

Question format to paste

Q: What force pulls objects toward Earth? | Friction | Gravity* | Magnetism | Air resistance | Gravity pulls everything with mass toward the Earth's centre.

(An asterisk marks the correct answer; the last field is the explanation.)

Check: the asterisk is removed from displayed text; explanations show for wrong answers only; teams rotate correctly after a timeout.

Make a one-screen 2D tower defense game. Cartoon beetles walk a fixed path of 6 waypoints from the left edge to a tree stump on the right. The player clicks or taps a grass tile to place a Leaf Turret for 25 coins; it shoots the nearest beetle within 120 px once per second. Start with 100 coins; each beetle gives 5 coins. The stump has 10 lives; each beetle reaching it costs 1. A Start Wave button sends 8 beetles. Show coins, lives and wave at the top. Shapes drawn in code, flat greens and browns. Restart button on game over.

Check after:

• Beetles follow the path exactly and never cut corners through grass.
• Turrets can't be placed on the path or on top of each other.
• Coins rise on each defeat; lives drop when a beetle reaches the stump.

If it breaks:

• *Beetles leave the path:* "Move enemies from waypoint to waypoint in a straight line at constant speed; when within 2 px of a waypoint, snap to it and target the next one. Don't change anything else."
• *Towers placed on the path:* "Mark path tiles as unbuildable using a grid; highlight buildable tiles on hover in green and unbuildable in red."

Make a cozy farming game with a 6x4 grid of soil plots. Tap a plot to cycle: till, plant, water. Seeds: Turnip (2 coins, 2 days), Carrot (5, 3 days), Pumpkin (12, 5 days), chosen from a seed bar. A Sleep button advances the day. Watered plots grow one stage per day (3 visible stages); unwatered plots don't grow. Tap a ripe plant to harvest into a basket. Start with 20 coins. Show coins and day.

Check: crops only grow when watered; watering resets each morning.

• [ ] I can describe the game in one sentence: the player does X to achieve Y while avoiding Z.
• [ ] The main action is fun on its own for 30 seconds, before any upgrades or levels.
• [ ] Every action gives an immediate visible result.
• [ ] There's a reason to do the action again (score, progress, story, collection).
• [ ] The game has a clear end state for a session (game over, level complete, day end) or a natural stopping point for idle/cozy games.
• [ ] I removed features that don't support the core loop.

Fix prompt: "Remove [feature]. It doesn't support the core loop. Don't change anything else."

• [ ] The game works with touch only, without hover.
• [ ] Touch targets are at least 48-64 px, with space between them.
• [ ] Multi-touch works (move and jump at once).
• [ ] The page doesn't scroll, zoom or pull-to-refresh during play.
• [ ] The game fits portrait and landscape, or clearly asks to rotate.
• [ ] HUD stays clear of notches and rounded corners.
• [ ] Audio starts after the first tap.