FREE & OPEN SOURCE
HTML5 Games
Free Vampire Survivors-Style Game — Single HTML File (Neon Swarm Survivor)
Neon Swarm Survivor: a bullet-heaven roguelite in one HTML file — auto-fire, orbital blades, XP crystals and level-up cards with 6 stacking upgrades. WASD or touch-drag, zero dependencies.
What it is
Neon Swarm Survivor compresses the Vampire Survivors loop into a single HTML file: you steer, the ship fires by itself at the nearest enemy, and the swarm never stops growing. Move with WASD/arrows on desktop or press-and-drag on touch screens.
Kills drop XP crystals that vacuum toward you inside your magnet radius; each level-up pauses the action and deals three random cards from a six-upgrade pool — extra barrels, faster trigger, higher damage, speed boosts, additional orbital blades circling you, and a vacuum field that also heals. Elites spawn at 12% odds with quadruple health, spawn rate ramps with survival time, and the run economy (fire delay, multishot count, orbital count, magnet range) all stack the way roguelite players expect.
Everything — the neon grid floor, glow effects, the level-up modal, the synthesized bleeps — lives in 462 lines of vanilla JS you can read in one sitting.
Kills drop XP crystals that vacuum toward you inside your magnet radius; each level-up pauses the action and deals three random cards from a six-upgrade pool — extra barrels, faster trigger, higher damage, speed boosts, additional orbital blades circling you, and a vacuum field that also heals. Elites spawn at 12% odds with quadruple health, spawn rate ramps with survival time, and the run economy (fire delay, multishot count, orbital count, magnet range) all stack the way roguelite players expect.
Everything — the neon grid floor, glow effects, the level-up modal, the synthesized bleeps — lives in 462 lines of vanilla JS you can read in one sitting.
Neon Swarm Survivor vs the usual way
The genre standard ships on Unity with hundreds of megabytes. This is ~10 KB and opens from a file:// URL.
| Feature | Neon Swarm Survivor (single file) | Typical engine-based equivalent |
|---|---|---|
| Files to deploy | 1 HTML file | Framework bundle + assets + build output |
| External dependencies | 0 | Game engine (Phaser/Unity/…) + toolchain |
| Art & audio assets | None — Canvas drawing + synthesized sound | Sprite sheets, audio files |
| Mobile touch support | ✓ built in | Varies |
| Embed with an iframe | ✓ anywhere | Usually |
| Readable, remixable source | ✓ ~462 lines, MIT | Minified bundles |
Server requirements & dependencies
- Any modern browser — desktop or mobile. Nothing else.
- No build step, no server, no game engine, no external libraries.
- No image or audio assets: every sound is synthesized live with the Web Audio API.
- Embeds anywhere with a plain <iframe>.
How to install
1. Download and unzip — you get index.html and a README.
2. Double-click index.html, or upload it to any static host (shared hosting, GitHub Pages, Netlify, an S3 bucket… anything that serves a file).
3. To embed it in an existing site: <iframe src="/games/index.html" width="860" height="620"></iframe>. That's the whole deployment story.
2. Double-click index.html, or upload it to any static host (shared hosting, GitHub Pages, Netlify, an S3 bucket… anything that serves a file).
3. To embed it in an existing site: <iframe src="/games/index.html" width="860" height="620"></iframe>. That's the whole deployment story.
The prompt — build it yourself
Paste this into Gemini and you'll get this product. This is the actual spec that produced the code above.
Community build: one of six HTML5 games generated by the site's owner with Google Gemini 3.1 Pro — each a true zero-shot: one prompt, one file, ~13 seconds of generation, no external libraries, images or audio (all sound is Web Audio synthesis). The exact prompt, verbatim (in Turkish, as written):
Vampire Survivors mekaniklerinden esinlenen, tek dosyalık saf HTML5 Canvas ve JS ile çalışan 'Neon Swarm Survivor' adlı bir Bullet Heaven / Roguelite oyunu kodla. Oyuncu WASD veya dokunmatik sürükleme ile hareket etsin, en yakın düşmana otomatik ateş etsin, etrafında dönen orbital bıçaklar bulunsun. Düşmanlardan XP kristalleri düşsün ve her seviye atlandığında oyunu duraklatıp 3 rastgele güçlendirme kartı sunan bir seçim ekranı açılsın.
Verified before publishing: every file read line-by-line, UI strings localized to English for this showcase, and each game deployed and played on the live demo. Upgrade cards apply and stack correctly (multishot spread, orbital count, magnet radius all verified in play).
Vampire Survivors mekaniklerinden esinlenen, tek dosyalık saf HTML5 Canvas ve JS ile çalışan 'Neon Swarm Survivor' adlı bir Bullet Heaven / Roguelite oyunu kodla. Oyuncu WASD veya dokunmatik sürükleme ile hareket etsin, en yakın düşmana otomatik ateş etsin, etrafında dönen orbital bıçaklar bulunsun. Düşmanlardan XP kristalleri düşsün ve her seviye atlandığında oyunu duraklatıp 3 rastgele güçlendirme kartı sunan bir seçim ekranı açılsın.
Verified before publishing: every file read line-by-line, UI strings localized to English for this showcase, and each game deployed and played on the live demo. Upgrade cards apply and stack correctly (multishot spread, orbital count, magnet radius all verified in play).
Reviews
Used Free Vampire Survivors-Style Game — Single HTML File (Neon Swarm Survivor)? A star rating takes two seconds and helps others.
More builds
Free Chevereto Alternative — Self-Hosted Image Hosting PHP Script (PixelZip)
Free Tower Defense Game — Single HTML File, No Engine (CyberGrid Defense)
Free Breakout Game with Roguelite Power-Ups — Single HTML File (Hyperion Breakout Pro)
Free Suika-Style Planet Merge Game — Single HTML File (Cosmic Merge 2D)
License: MIT — free for personal and commercial use, no warranty. Software is provided as is; review the code before running it in production (it's short enough to actually read).