Why File Size Matters
Every 1MB over 2.5MB costs 12% completion. At 6MB (agency average), you lose 42% before they see your game.
Trick 1: WebP + SVG Over PNG
WebP at 90% quality saves 80% file size. SVG for UI elements. A fishing game went from 5.2MB to 2.1MB.
Trick 2: Strip Dead JavaScript
Average 180KB unused JS per playable. Replace physics engines with manual checks. CSS animations over tweening libs.
Trick 3: Opus Audio at 32kbps
30-second soundtrack: 480KB (MP3) vs 120KB (Opus). 10-second loops save 60%. Web Audio API for SFX.
Trick 4: Reduce Sprite Framerate
12fps idle, 20fps gameplay cuts spritesheet size 50-60%. Users don't notice on mobile screens.
Trick 5: CSS-Only Rendering
CSS-only playable: 380KB. Canvas equivalent: 2.1MB. 60% of hypercasual can be CSS-only.
Cumulative Effect
6.8MB to 1.7MB (75% reduction). Load 4.2s to 1.1s. Completion 48% to 73%.