Recreating Childhood: Building a 4399‑Style Game Suite in One Hour with Doubao‑Seed‑Evolving

Environment Setup

Created a Volcano Engine account, enabled the Doubao‑Seed‑Evolving model, and obtained an API key. Integrated the model as a custom model in the Vibe Coding IDE (Trae), allowing direct selection of Seed‑Evolving in the IDE’s agent dialog.

Flappy Bird with Two‑Player Mode

Prompted the model to implement a classic Flappy Bird in native HTML/CSS/JS with a competitive two‑player mode (space bar for one bird, W for the other). To improve prompt quality, a separate LLM (DeepSeek) reorganized the request into a structured prompt:

你是一名资深Web游戏开发工程师，精通HTML5、CSS3、JavaScript及Canvas 2D。
需要完整复现经典游戏Flappy Bird，并扩展双人对战模式。

一、游戏核心机制（参考原版Flappy Bird）
二、模式一：单人模式
三、模式二：双人模式（核心扩展）
四、功能与交互要求

Feeding this prompt to Doubao‑Seed‑Evolving returned a complete codebase in a single round, with files bird.js (bird physics and animation), pipe.js (pipe generation and recycling), game.js (main loop and collision detection), and main.js (menu and mode switching). The two‑player logic assigned separate input keys and independent physics, scoring, and collision detection. A short play test confirmed the intended competitive experience.

3D City Racing Game

Requested a 3D racing game using Three.js, with dynamic difficulty, a city‑skyline background, and panoramic images loaded based on a city name. The same prompt‑refinement workflow was applied:

你是一名资深Web 3D游戏开发工程师，精通Three.js、WebGL、JavaScript（ES6+）以及前端工程化。现在需要你开发一款3D城市赛车躲避游戏，核心机制围绕“沉浸式驾驶体验”和“动态难度递增”展开。请严格遵循以下需求完成开发：
一、游戏核心机制
二、沉浸式背景（核心亮点）
三、控制与交互
四、技术实现与项目结构
性能优化：

Initial generation failed due to two issues:

Panoramic image loading from Wikimedia Commons failed because required width/height parameters were missing and the host is blocked in China.

The coordinate system was misaligned: the car moved toward the camera, and its position accumulated while the world scrolled in the opposite direction, causing the car to leave the scene.

After describing these symptoms, the model identified the problems and suggested fixes: keep the player fixed at the origin, move the world with modular arithmetic, and add lane‑specific spawning logic. After three to four refinement rounds, the game displayed a dusk sky, city silhouettes, functional increasing speed, and correct lane behavior.

4399‑Style Game Hub

Asked the model to generate a 4399‑style game platform page with an orange navigation bar, banner carousel, category sidebar, ranking list, and iframe‑based game launch. Within minutes the model produced a functional HTML page with responsive layout, hover effects, search filtering, and the required UI components.

Full source code is available at https://github.com/TangBaron/4399_game

Reflections on Model Capabilities

Doubao‑Seed‑Evolving reliably generated standard game logic and converged after multi‑turn dialogue when provided with descriptive feedback. However, it struggled with spatial reasoning (coordinate system alignment), third‑party resource availability (panorama image loading), and network constraints (blocked hosts). Human oversight remained necessary to verify resource accessibility and guide geometry‑related corrections.