Hisar: Fortress Defense
A low-poly 3D tower defense on the Bosphorus: build archers, cannons and tar cauldrons along two roads and hold a seaside fortress for 15 waves. The README says Claude Opus 5.5 built it with Claude Code from one prompt.
Official site furkiozknn.github.io, verified Nov 3, 2026. Linked as “Play now” and “Play online” in the README of the developer's Furkiozknn/kale-savunmasi repository.
Where to play
Every platform this game is on. Links are checked against official sources; we never host or mirror games.
- Play free — official siteBrowserReleased · Desktop and phone; touch devices start on Low qualityFree
Runs in a desktop or mobile browser. No download.
Browser (no download) · Mobile · Official link verified Nov 3, 2026.
- Play free — itch.ioitch.ioReleasedFree
Plays in the browser on itch.io. No download.
Browser (no download) · Mobile · Official link verified Nov 3, 2026.
- View on GitHubGitHubReleased · Source code (MIT), including the original prompt in prompts/hisar.mdFree
Download from the GitHub releases page.
Desktop · Official link verified Nov 3, 2026.
About Hisar: Fortress Defense
Hisar is a free low-poly 3D tower defense game in the browser, set at a fortress (hisar in Turkish) on the shore of the Bosphorus. An army marches from two camps along two roads that merge before the gate; you build on stone pads beside the road and try to keep 20 lives through 15 waves, after which endless mode keeps raising the pressure. There are three towers with three levels each: the Archer Tower fires fast single-target arrows, the Cannon Bastion lobs shells at a predicted landing point for splash damage, and the Tar Cauldron slows and burns and leaves sticky tar on the road. Four enemy types come at you: Raiders, fast Riders, armoured Shieldbearers that shrug off arrows, and a Battering Ram boss on waves 5, 10 and 15 that costs six lives if it reaches the gate. Each tower has three target modes (First, Strongest, Nearest), can be sold for a 70% refund, and you can call the next wave early for bonus gold and play at 1x, 2x or 3x speed. The run is saved after each cleared wave. The scenery has limestone walls and slate-roofed towers, choppy water and a far shore with a mosque, and the interface looks like a war table of parchment and wax seals; the music is a loop in the Hicaz mode synthesised in the browser. It plays on desktop and on phones, in English and Turkish. The README says it was built by Claude Opus 5.5 with Claude Code from one prompt, and that a later asset remaster and a November 2026 redesign were also done by Claude Opus 5.5. Free on itch.io and GitHub Pages, with the source on GitHub under the MIT licence.
How it was built
Partially verifiedThe README says the game was built by Claude Opus 5.5 with Claude Code from one prompt, which the repository publishes in prompts/hisar.md: a detailed brief for a single-file Three.js tower defense covering the world, enemies, rules, controls and a self-test bot, ending “Do not ask questions, build it end to end.” The first version was fully procedural, with low-poly models built from primitives and every sound effect synthesised with Web Audio; the music was added later. The README names Claude Opus 5.5 as the orchestrator of a later asset remaster and of the November 2026 redesign, which rebuilt the fortress and tower bases in code. Balance was tuned with the built-in ?auto bot, which falls on wave 15 in the measured run.
- Developeritch.io page: “One of a series of free 3D browser games with a Turkish setting, built with AI (Claude Code by Anthropic).” — itch.io
One index.html with Three.js r170 loaded from a CDN, plus a few asset files. The README says the first version was built entirely in code from a single prompt; for the remaster the models for the enemies, turrets and boats (and at first the fortress and tower bases) were generated with Tripo text-to-3D through Higgsfield and processed with glTF-Transform, and GPT Image drew a 16-icon sheet and the logo crest, with every procedural model kept as a fallback. The November 2026 redesign replaced the generated fortress and tower-base models with textured ones built in code, added the Asian shore and a war-table interface with a self-hosted OFL stencil font, and was measured at 60 fps on an Intel UHD 620 in headless Chrome. Tower and enemy data sit in two tables at the top of the script and were tuned with the ?auto bot. Settings, the run and the best wave are stored in localStorage; GoatCounter counts visits.
- Engine / framework
- Three.js
- Languages
- JavaScript
- Team size
- Not disclosed
- Development time
- Not disclosed
- Development cost
- Not disclosed
- AI-written code
- Not disclosed
“Built by Claude Opus 5.5 with Claude Code from one prompt: prompts/hisar.md.”- Furkiozknn/kale-savunmasi on GitHub (README: How it was made)
- The one prompt the game was built from (prompts/hisar.md)
Verification notes: AI use, rules, the remaster and the redesign from the repository README and prompts/hisar.md, read as raw files on 4 Nov 2026; the itch.io page, re-read the same day, says the series is built with AI (Claude Code by Anthropic), and its AI disclosure field reads “AI Assisted” for code, graphics, sounds and text (itch.io's own label set). The README does not give an AI code share, so none is recorded. Generated 3D models (Tripo, through Higgsfield) and images (GPT Image) are assets, described in the build text. The itch.io page was published on 28 Oct 2026 (17:40 UTC) and last updated on 3 Nov 2026 (00:56 UTC); the GitHub Pages build may be older, and since the github.com page and API were not reachable from our session the overall release date is left blank. The game page (page language tr) loaded on 4 Nov 2026; apart from Three.js from a CDN and the GoatCounter counter it makes no network requests, so no AI service runs during play. Languages: the itch.io page says English and Turkish, following the browser language. The licence file is MIT (© 2026 Furkiozknn). The README mentions a Godot 4 remake made in a second round; we did not find or check it. The other games in the Claude Game Arena series are not covered by this record. The game was not played through.
Development history
Published on itch.io (17:40 UTC).
Observeditch.io- November 2026
Redesign by Claude Opus 5.5: the fortress and tower bases are rebuilt in code, the far shore is added and the interface becomes a parchment war table.
DeveloperGitHub (Furkiozknn) The itch.io page is updated (00:56 UTC).
Observeditch.io
Game performance
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Browser (official site)
No public metrics recorded for this listing.
Not publicly available: Concurrent players (site), Monthly revenue, Gross revenue.
itch.io
No public metrics recorded for this listing.
Not publicly available: itch.io rating, Gross revenue.
GitHub
No public metrics recorded for this listing.
Not publicly available: GitHub stars.
Sales & revenue (all platforms)
Browser game — there are no downloads to count.
Reviews & rankings
Not yet reviewed by our editors.
Not currently ranked.
Sources
| Source | Type | Published | Accessed |
|---|---|---|---|
| kale-savunmasi — README GitHub (Furkiozknn) · English | Repository | Not confirmed | Nov 3, 2026 |
| Game 01: Hisar (prompts/hisar.md) GitHub (Furkiozknn) · English | Repository | Not confirmed | Nov 3, 2026 |
| Kale Savunması: Fortress Defense by FurkiOzkan itch.io · English | Store page | Oct 28, 2026 | Nov 3, 2026 |
