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Attract loop · play it for real in the Preview tab
What MIA is building
Score 0
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Goal 50
Cat & Pianos
Controls arrows to move
Game logic
Every slider re-tunes the running game instantly. MIA writes these too — you can overrule it.
Difficulty & pacing
The numbers behind the feel.
When → Then rules
Plain-language view of the current spec.
Extra rules
Real toggles — they change how the game plays.
Start with a shield
First hit is free every life.
Speed up on pickup
Each collectible nudges the pace.
Bonus life at combo 10
Reward a clean streak.
Level builder
Design the course one piece at a time. Changes rebuild the running game instantly.
Screens & music
A title screen, a cinematic intro, ending screens and a soundtrack — wraps around any game.
Cover / thumbnail
Paint the level, tile by tile
Open a full canvas and build the stage with the brick, stone, grass, aztec and ice tiles — paint a background, block out platforms, and mark each tile solid, one-way (jump up through, land on top) or destructible.
Story & dialogue
Speech-bubble text that plays during the game, with a typewriter effect. Leave a blank line for the next page.
Art & Assets
Replace the cast with your own art, repaint the palette, and jump between versions of your game.
Ready-made characters
Tap one to make it your player. Original art — every game still looks different because you pick the cast, colours and level.
Side-scroll heroes — platformer, runner, endless
RPG & top-down cast
Vehicles — racing, chase, top-down
Cast
Type a word (fox, ninja, robot…), paste an emoji, tap a preset, or upload art.
Player
Hazard / enemy
Collectible
⋯
Background
Design one with layers & photos, or drop an image.
Art is downscaled to 128px and kept with the game. Big files may be too large to publish.
Palette & HUD
Six colours drive the whole look.
Background
Accent / HUD
Player tint
Hazard tint
Collectible tint
Crunches the finished frame — palette, pixel size and scanlines. Applies to every game you build.
Versions
Every MIA change is pinned automatically. Jump back any time.
Publish to Crystal Arcade
Ship a playable link, set how it earns, and it lands on Crystal Arcade for the whole community to play and comment on.
Cat & Pianos
Dodge the falling pianos.
Also ship to desktop
The same project runs as a native app — Windows, macOS, Linux — by wrapping this engine in Tauri. What changes on desktop:- Projects save as local
.harmonyfiles you own - MIA runs offline against your own Claude API key
- Native menus, drag-drop assets, full-screen playtest
Your share80%
On a $2.00 sale you keep $1.60. Harmony takes 20% for payments, hosting and the Arcade. Payouts via Stripe Connect.
Prototype note — real vs. wired-up
- Real here: the engine, MIA, live tuning, the Crystal Arcade feed, comments, likes, presence and chat (shared across everyone in your workspace).
- Wired-up next: Stripe payouts, public accounts and a public web domain need the Harmony backend — see your engine-architecture doc.
seed ————
MIA · starting…
Gems 0/0
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explore
WASD move · Space jump · drag / arrows to look