Free Tower Defense Game — Single HTML File, No Engine (CyberGrid Defense)

CyberGrid Defense is a complete tower defense game — the genre that usually ships on Phaser or Unity — in one engine-free HTML file. Enemies stream along a neon waypoint route across a 19×11 grid; you place towers on any non-road cell and click them again to upgrade, five levels deep.

The four tower classes actually play differently: the Pulse Laser is your cheap single-target workhorse, the Cryo Node applies a 48% slow, the Plasma Cannon deals splash damage in a radius, and the Railgun trades fire rate for huge single-hit damage at nearly double the range. Every fourth wave delivers a boss with 3.5× health. Enemy health bars, beam flashes, explosion particles and the glowing path are all drawn straight onto Canvas; all audio is oscillator-synthesized.

Because the path is a simple waypoint array and the towers are a four-entry table, remixing it — new maps, new tower types, different economy — is a ten-minute text edit, not an engine project.

Feature	CyberGrid Defense (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	✓ ~495 lines, MIT	Minified bundles

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.

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, ~14 seconds of generation, no external libraries, images or audio (all sound is Web Audio synthesis). The exact prompt, verbatim (in Turkish, as written):

Tek bir HTML dosyasında çalışan, sıfır harici bağımlılıklı 'CyberGrid Defense' adında neon vektör grafikli bir kule savunma (Tower Defense) oyunu geliştir. 19x11 ızgara sistemi, önceden tanımlı waypoint rotası, 4 farklı kule sınıfı (tekli lazer, yavaşlatıcı cryo, alan hasarlı plazma, uzun menzilli railgun), kule yükseltme mekaniği, her 4 dalgada bir gelen Boss düşmanlar ve Web Audio API ses efektleri bulunsun.

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. Tower placement is correctly blocked on road cells and upgrades scale damage and range as advertised.