Pet Rescue Line Project Report
1. The Concept
Pet Rescue Line is a 2D drawing-and-physics puzzle game in the spirit of “Save the Doge.” The player traces one continuous ink line to shield a cartoon dog from a bee swarm. After the stroke is released, the line becomes a Matter.js barrier: a well-supported or closed shield holds, while a weak stroke can be shoved aside. Bees burst from hives, hunt the pet, and try to slip through gaps. Survive 10 seconds to win. Using less ink earns more paw medals. Ten levels teach new layouts one at a time — open meadow, cliffs, water gaps, wooden pegs, sky steps, two-hive crossfire, stone ledges, caves, lava pits, and a three-hive siege.
2. The Stack
The Stack: HTML5 Canvas, CSS, vanilla JavaScript modules, and Matter.js 0.20.0 for rigid-body physics. Pointer Events handle mouse, touch, and pen drawing. A local Python http.server (via start-game.bat) serves the static game. Progress is stored in localStorage. Original WebP art, UI, BGM, and SFX live under assets/.
The AI Assist: Cursor (Grok 4.6) was used as a pair programmer for gameplay, bee AI, level design, and UI. The agent read the canvas/physics code, iterated on swarm pathfinding, restyled settings, expanded the campaign to 10 stages, and added a home-screen level picker. Design notes in sakurai/ and rules/ stayed in the repo as the product compass.
3. The 1 Day Sprint:
Morning (Hours 1–3): Locked the loop and the look. Home is a 16:9 sanctuary with Play, Levels, and Settings. Settings covers music, sound, and How to Play in English. Gameplay uses a meadow playfield, grassy platforms, and the in-game Shiba on win/lose cards. Drawing, ink, the 10-second timer, and Matter.js line bodies were already playable; the morning pass made the product feel like a real mobile puzzle instead of a prototype.
Afternoon (Hours 4–6): Spent on feel. Bees were ramming one spot on an open arch instead of splitting toward holes. Pathfinding was rebuilt: closed loops still get pressed; open strokes slide along the outside to real gates; bees split over, beside, and under a floating island, but they do not dive under solid ground. The ink stroke was thinned and smoothed so it reads as a simple marker, not a fat crayon. Weak lines stay put until impact; a stroke sitting on a rock counts as supported.
The Finish Line (Hour 7-8): Grew the campaign from 6 to 10 uniquely staged levels and replaced the old “Levels” shortcut (which jumped into stage 1) with a gold-bordered 1–10 grid, locks, and continue on Play. Late-game full-width lava oceans were pulled back so the meadow shows and unanchored shields are not eaten by a fake sea. Cache-busting versions were bumped so a hard refresh picks up the new game.js.
4. The Roadblocks
Roadblocks: Bee AI fought itself. A “fly straight at the dog” swarm matched a reference video on closed shields, then ignored every hole. Duplicate lineEscapeTarget functions meant the old ram-the-wall logic won. Tips near grass were treated as planted, so an inverted-U with a gap counted as sealed. Auto-closing loops within 90px welded player-made holes shut. Gates under a floating island sent bees into the dirt, while a later over-correction banned all under-flights. Drawing a dome that only sat on the rock (ends not snapped) still fell. Full-width lava on later stages looked like water under every draw. Portrait phones, file:// module loading, and “the game won’t open” without a local server cost extra time.
5. Key Takeaways
A physics puzzle lives or dies on one readable rule: what the line does when bees hit it, and whether a visible gap is really a gap. Pathfinding must match what the player sees — split around floating rocks, never tunnel through solid ground, and enter a hole that looks bee-sized.
Ten levels only work if each one teaches a new obstacle, not the same two islands with a higher bee count. Play continues; Levels must show the map.
My final thought: Pet Rescue Line is a complete 10-level browser toy after one focused sprint, but the swarm will always need playtesting with a real finger on a real arch. Ship the loop, then keep chasing the moment when bees find the hole the player left on purpose.