Run, jump and land. Platformers live or die on how the jump feels, so describe it carefully and fix it before adding levels.
Tips for platformer games
Ask for coyote time (a short grace period to jump after leaving a ledge) and jump buffering in the first prompt. They are the cheapest way to make jumping feel fair.
Describe levels as text grids (# for ground, C for coin, E for enemy). The AI builds levels from a grid much more reliably than from descriptions.
Ask for variable jump height: releasing the jump key early cuts the jump short. It gives players control without extra buttons.
starter
First jump
Make a simple 2D platformer on one screen. The player is a small square character with eyes. Left/right arrows or A/D move, Space/W/up jumps. On touch screens show left, right and jump buttons. Gravity pulls down; jump height about 3 tiles. Add coyote time (0.1 s) and jump buffering (0.1 s). Build the level from this text grid where # is ground, C is a coin, F is the flag:
..........C.......F
.......####....####
...C..........#....
..####....C........
#########.####.####
Falling off the bottom restarts the level. Collect coins (+10 each); touching the flag shows 'Level complete' with the score. Pastel colours, smooth camera.
A text-grid level and named feel settings (coyote time, buffering) give a solid result on the first try.
Follow-up tweaks
Make the jump higher when I hold the button and shorter when I tap it.
Add a second level grid and a 'Next level' button on the complete screen.
starter
Coin climb
Make a vertical platformer. The player climbs upward on platforms that are generated randomly but always reachable (no gap wider than the jump distance). The camera scrolls up as the player climbs and never goes back down. Falling below the bottom of the screen ends the run. Controls: left/right to move, automatic bounce when landing on a platform (no jump button). On touch, tap left or right half of the screen. Score is height; coins add 50. Some platforms crumble 0.5 seconds after landing. Sky gets darker and starry the higher you go.
Auto-bounce plus a reachability rule removes the hardest parts of a platformer and keeps it mobile-friendly.
Follow-up tweaks
Add spring platforms that launch the player twice as high.
Add a moving cloud platform that drifts left and right.
intermediate · tested ✓
Wall-jump tower
Make a platformer focused on wall jumping. The level is a tall narrow shaft built from a text grid (# walls, S spikes, C coins, F finish at the top). Moving into a wall while falling makes the player slide down slowly. Pressing jump while sliding launches the player up and away from the wall. Include coyote time and jump buffering. Touching spikes respawns at the last checkpoint flag (P in the grid). Show a timer and death count. Camera follows vertically with smoothing. Make 3 shafts of rising difficulty, each about 40 rows high.
Explaining the wall-slide and wall-jump in steps tells the AI exactly which states the player needs.
Follow-up tweaks
Add a dash on Shift / a dash button: a quick horizontal burst usable once per airtime.
Show a ghost of my previous best run.
intermediate
Gravity flip runner
Make a platformer where the player can't jump; instead, pressing Space or tapping flips gravity so the character falls to the ceiling or back to the floor. The level scrolls automatically to the right at a steady speed. Spikes on floors and ceilings end the run. Gaps must be crossed by flipping at the right time. Use a level grid of 200 columns made of a few hand-made chunks joined in random order. Score is distance; best score saved. Speed increases slightly every chunk. Neon lines on black, the player leaves a short trail.
Joining hand-made chunks gives designed difficulty with endless variety.
Follow-up tweaks
Add portals that reverse the scroll direction for a short section.
Add a practice mode with checkpoints every chunk.
advanced
Metroidvania room
Make a small exploration platformer with 6 connected rooms, each one screen, laid out in a 3x2 map. Leaving a room's edge moves to the next room. The player starts unable to double jump; a glowing orb in room 4 unlocks the double jump, and a key in room 5 opens a door in room 2 that leads to the exit. Show a mini-map in the corner with visited rooms filled in. Enemies: slow walking blobs that bounce the player back and take 1 of 3 hearts. Hearts refill at a save statue (touch it to save position). Levels defined as text grids per room. Moody cave palette with one bright accent per collectible.
Spelling out the ability gate and the key/door link gives a real exploration loop in a tiny world.
Follow-up tweaks
Add a wall-cling ability as a second upgrade that opens a secret room.
Save progress (rooms visited, abilities) to localStorage.
intermediate
Moving platforms and switches
Make a puzzle platformer with 5 levels. Each level has platforms that move between two points, and coloured switches that toggle matching coloured blocks between solid and see-through. The player rides moving platforms correctly (moves with them, doesn't slide off). Reach the door to finish. Controls: arrows/WASD + Space, touch buttons on mobile. R restarts the level. Show the level number and a step-free hint button that briefly highlights the next switch. Clean flat style, each switch colour also has a shape icon so colour-blind players can tell them apart.
Mentioning that the player must ride platforms prevents a very common physics bug.
Follow-up tweaks
Add a timed switch that flips back after 5 seconds with a countdown ring.
Add a level select screen showing which levels are done.
starter
Speedrun one-screen challenge
Make a one-screen platformer challenge. The screen is filled with small platforms, a start at the bottom left and a goal star at the top right. A timer starts when the player first moves and stops at the star. Hidden shortcuts exist for skilled players. Show the time to two decimal places and the best time. R or a restart button resets instantly (no menus). Controls: arrows + Space with coyote time and variable jump height. Simple black and white style with a red player.
An instant restart and visible timer are the whole hook of speedrun games.
Follow-up tweaks
Add 5 collectible gems that add a 'all gems' category to the best times.
Make 3 more one-screen levels with a level picker.
starter
Kids' bouncy garden
Make a gentle platformer for young children. The character is a round bunny. Arrow keys or big on-screen arrows move; one big jump button. There are no enemies and no way to lose: falling into water just bounces the bunny back to the nearest platform. Collect 10 carrots spread across a garden that scrolls sideways. Each carrot makes a happy chime and counts on a big carrot counter. When all 10 are collected, flowers bloom and confetti falls. Soft colours, rounded shapes, large text.
Removing failure states makes a platformer suitable for small children without changing the core controls.
Follow-up tweaks
Add a second garden with butterflies that follow the bunny.
Read out the carrot count with speech synthesis when one is collected.
advanced
Grappling hook swing
Make a side-scrolling platformer with a grappling hook. Click/tap a hook point (shown as rings in the air) within range to attach a rope; the player then swings like a pendulum with rope length fixed at the attach moment. Release with click/tap again or Space to fly off with current momentum. Arrow keys add a small push while swinging. Falling into the pit at the bottom restarts from the last checkpoint. Course of 3 sections with rising gaps. Show the rope as a line and highlight the nearest reachable ring. Timer and best time.
Describing the rope as a pendulum with fixed length is enough for the AI to pick a stable approach.
Follow-up tweaks
Let the player shorten or lengthen the rope with up/down while swinging.
30 fill-in master templates with worked examples, 12 multi-step build recipes (what to prompt, what to check after each step, and the fix prompt when it breaks), 40 bug-fix prompts by symptom, 20 art-direction briefs with upload tips, and a game-design + launch checklist. Markdown files, instant download.
One-time $12. Use and adapt the prompts in your own games, commercial ones included. 14-day fix-or-refund if it doesn't work as described. Secure checkout by Stripe.
Free sampler
T01 · Path defense master template (template)
Use it for: classic tower defense with a fixed route and placed towers. The most reliable starting point for the genre.
Variables
Variable
What to write
Example
{{theme}}
Setting in a few words
backyard garden
{{enemy}}
Who walks the path
slugs
{{base}}
What the player protects
the garden gate
{{waypoints}}
Path as a waypoint description
6 waypoints snaking left to right
{{tower_1..3}}
Name, price, role
Pea Shooter, 25, single target
{{start_money}} / {{reward}}
Economy
100 / 5
{{lives}} / {{waves}}
Lose and win conditions
10 / 12
{{palette}}
Visual style
flat bright greens and browns
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."
T13 · Classroom quiz engine template (template)
Use it for: any subject quiz you'll reuse with new questions every week.
Variables
Variable
Example
{{subject}}
Year 6 science: forces
{{questions}}
your list, pasted in the format below
{{timer}}
20 seconds, or "no timer"
{{teams}}
2 to 4 teams, or "single player"
{{reward}}
a star burst and a "Great thinking!" message
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.
Ship a tower defense in 6 prompts · Step 1 of 6 (recipe-step)
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."
A cozy farm in 8 prompts · Step 1 of 8 (recipe-step)
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.
Checklist · Core loop (checklist)
[ ] 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."
Checklist · Mobile and touch (checklist)
[ ] 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.