Artillerie, quatre variantes

Vibe Coding Challenge: "Artillery"
The task
Build a two-player artillery game as one standalone HTML file. Two castles stand on a 2D landscape that is newly generated for every game, each with an artillery gun mounted in its middle. The players take turns aiming and firing at each other's castle until one is destroyed. Both players play on the same device and pass the controls back and forth after every shot. There is no computer opponent.
The goal is the best possible version of this: beautiful graphics, satisfying sound, and smooth, fun gameplay.
The genre, briefly
This is a classic artillery game: side view, a landscape of hills and valleys, and shots that fly in an arc pulled down by gravity and pushed sideways by wind. Each turn the active player sets the barrel angle and the shot power, then fires. Explosions blow craters into the ground and smash parts of the castles. The fun comes from reading the terrain and the wind and adjusting your aim after every miss.
Requirements
Map

* Generate a new landscape for every game, with natural-looking hills and valleys. It must be fair: castles at roughly equal height and distance, and no terrain that makes hitting the other side impossible.
* Put one castle on each half of the map, each with a gun in its middle.
* Make the terrain destructible. Explosions carve craters, and the craters stay for the rest of the game.

Turns and controls

* Players alternate strictly: player 1, then player 2, then player 1 again. Who starts the first game is up to you, but it must be fair over a rematch.
* The active player adjusts the angle and the power, then fires. It must work with the keyboard and with the mouse or touch.
* The screen must always make clear whose turn it is, the current angle and power, and the wind.
* Wind changes between turns and affects the shots in a way players can see and understand.

Physics and combat

* Shots fly on believable arcs under gravity and wind.
* Hits damage the castles visibly, and a castle's state (for example its health or its remaining structure) must be easy to read.
* A player wins by destroying the other castle. Show a clear victory screen with an option to play again on a new map.
* You decide whether to add extra ammunition types, special shots or other mechanics, but only if they make the game more fun and not more confusing.

Graphics

* Aim for the best-looking game you can make: an atmospheric sky, a detailed landscape, castles with character, and juicy effects such as explosions, debris, smoke, screen shake and shot trails.
* Generate all graphics in code. No image files and no external assets.

Sound

* Generate all sound in code with the Web Audio API: cannon fire, the shot in flight, explosions, hits, the turn change and the victory, plus ambience or music if you like. No audio files.
* Include a mute toggle.

Technical

* Deliver a single HTML file that runs offline by opening it in a current desktop browser. No libraries, no CDNs, no external fonts, no network requests.
* It must not store any data: no localStorage, sessionStorage, cookies or IndexedDB.
* It must run smoothly (target 60 fps), adapt to the window size, and throw no console errors.

Competition rules

* Build from scratch, using only this brief. Do not search connected repositories, drives or the web.
* Work on your own until the game is finished. I won't give feedback or answer questions during the build, so wherever the brief leaves something open, decide for yourself.
* Write the game from scratch. Don't look for existing versions of this game or reuse their code.
* If you can run code or open a browser in this environment, test the game as much as you like before you hand it over. If you can't, check your code carefully instead.
* Deliver the finished game as one complete HTML file. If you can create files, save it as an HTML file whose name contains your model name, version and effort level (for example `artillery-<model>-<version>-<effort>.html`). If you can't, put the entire file in a single code block, without shortening or leaving out any part of it.
* After the file, write at most five sentences: what you're most proud of, and what you'd improve with more time.

How the games will be judged

1. How much fun it is to play: the feel of the controls, the physics, the fairness, and wanting one more round.
2. The graphics and visual polish.
3. The sound design.
4. Stability: no bugs, no errors, smooth performance.