Two characters begin together on one bank: the Weaver (Vega) and the Herder (Altair). Midway through, a river tears the screen apart and separates them for good. The slice ends when the Weaver threads a line the Herder can no longer reach.
It's themed on La Dispute's Somewhere at the Bottom of the River Between Vega and Altair and the Qixi folktale behind it.
Built in plain JavaScript and Canvas: one page, no framework, no build step. Move with the arrow keys or WASD. The rest of the controls are left for you to find.