Sector Run

Three sectors, 960 pixels, one direction. The window advances on its own and you are pinned inside it — fall behind and the edge of the world carries you; get shoved into an asteroid by the scroll and that's a crush. ← → ↑ ↓ steer, hold Z / Space to fire. Dodge the drones, chew through the fields, secure the golden core at the far end.

What makes it a shmup

1. The forced window — the camera has somewhere to be, and it isn't asking. Three lines: advance scrollX, clamp the player into the window, and hurt({ type: 'crush' }) when the scroll presses you into a wall. That last line is the genre's whole personality. (Tutorial 10 quotes it.)
2. The stitched run — the level is three ordinary rooms with exits, composed into one map by a single stitchRooms call. Add a fourth sector by adding a room and a seam.
3. The ship — the ordinary Player in a movement: 'topdown' profile (no gravity, 8-way steering), wearing a custom sprite. On the floor plane fire isn't a jump, so holding it shoots.
4. The core — the pods are bonus items (score only); the golden core is the level's only true collectible, so taking it completes the world — the win condition costs no code at all.

Download & remix

One file, live in the SOURCE panel above — edit and RUN ▶. Take it home: main.js · engine bundle. Remix ideas: drone waves with entry patterns; a boss where the scroll stops; an Exit door instead of the core, demanding every pod.