Show HN: I made a Doom-like game fit inside a QR code

Original Article ↗ Hacker News Discussion ↗

QR Code Scanning & Platform Compatibility

  • Many reports that iOS’s native camera says “No usable data found”; explanation that iOS camera won’t treat data: URIs as clickable targets even when the payload is tiny.
  • Workarounds suggested:
    • Use a web-based QR decoder (e.g., upload the PNG and copy the decoded URI).
    • Use third‑party QR apps or desktop software that accept image input.
  • Initially the game didn’t support mobile controls and was effectively desktop‑only; later, after size optimizations, limited touch support was added for Chromium-based mobile browsers.
  • Several users saw a black screen on Firefox/iOS/Android; fixes were pushed and later reports say it works, though some browser quirks (focus, key mapping) remain.

Data URLs, Compression, and Size Golf

  • The QR encodes a data:text/html (originally base64) payload; discussion on:
    • Using raw text data: URIs vs base64 to shave bytes.
    • Browser restrictions on top‑level data: navigation (bookmarks vs links).
    • Using DecompressionStream and tight HTML/JS trimming to free more space.
  • A PR reduced payload size enough to add touch controls, better movement, and enemies.
  • Side discussions reference similar micro‑demos, procedural games, and WASM-in-QR projects.

Security & Malware Concerns

  • Multiple commenters worry about “running code from a QR code.”
  • Others argue this is equivalent to opening any arbitrary URL with JavaScript; the real risk is malicious sites, not the QR format itself.
  • Historical exploits via image/audio parsers are mentioned as examples of what’s possible if decoders are buggy.
  • Some propose standard or UX improvements (e.g., enforcing human‑readable URL text matching the QR).

Design Choices, UX, and Aesthetics

  • Debate over using image-rendering: pixelated: some prefer crisp pixels; the author prefers the blurrier, “retro” look.
  • Criticism that a QR-based game not primarily targeting phones is a “design issue”; the author cites tight size budget for mobile UI but invites others to build variants with the compression tooling.
  • Multiple requests for screenshots/GIFs instead of only a trailer; a GIF and gameplay media were later added, plus a hosted version to bypass scanning.

Technical & Conceptual Spin‑offs

  • Explanations of QR capacity and 8‑bit mode enabling arbitrary binary data; examples include encoding RSA keys and prior “game-in-a-QR” work.
  • Ideas floated: QR-embedded 3D print files, low-resource comms via QR over SSTV, self-contained P2P chat (blocked by browser limits), and even “LLM in a QR”–style experiments.