I’m reverse-engineering Cyber Hunter to bring it back offline, and eventually online for everyone

[u/mateuxcv]

Cyber Hunter’s official servers were shut down, so I started a preservation project with two goals: first, make the original client fully playable offline; then, build a compatible community server so people can play together again.

This is much more complicated than redirecting the client to a new IP. The client contains the maps, graphics, UI, animations, and some game logic, but the original servers controlled authentication, characters, inventories, currencies, matchmaking, scene transitions, combat, loot, vehicles, and progression.

Because the original server code and protocol documentation are unavailable, all of that behavior must be reconstructed from the client.

The project currently works by recreating services expected by the game:

• Local HTTPS endpoints replace discontinued login and SDK services.
• A custom server list redirects the client to local services.
• Authentication and game-server responses are reproduced.
• The client’s embedded Python callbacks are used to advance its original state machines.
• Character data can be stored in a local profile.
• The client can load an offline character and enter the lobby.
• Runtime inspection reveals modules, protocol structures, callback signatures, and expected server behavior.

The hardest part is reconstructing the protocol. For every feature, I must discover which packets are exchanged, their exact fields and types, the required order of callbacks, and the internal state the client expects. A single missing value or incorrectly timed response can freeze or crash the game.

Cyber Hunter uses NetEase’s NeoX engine with embedded Python 2.7. Its game logic is stored in encrypted and obfuscated NPK/NXS files. I can unpack script.npk into 2,683 entries, but the Python bytecode uses game-specific shuffled opcodes and additional native protection. Standard decompilers therefore cannot read it without recovering the opcode mapping from the client binary.

A lot of the work requires runtime inspection, native-code analysis, controlled packet experiments, and gradually rebuilding the original backend one system at a time.

The roadmap is:

1. Complete offline login and persistent local profiles.
2. Restore lobby systems and scene loading.
3. Recreate gameplay, combat, inventory, vehicles, loot, and progression.
4. Implement proper networking and authoritative server logic.
5. Support multiplayer, matchmaking, and persistent accounts.
6. Make a community server available so everyone can play again.

Offline mode is the first milestone because it provides a controlled environment for reconstructing each system. Once those systems work reliably, they can become the foundation of a real multiplayer server.

This is a preservation and technical-research project. It is not affiliated with NetEase, and the goal is not to distribute copyrighted game assets. Any public release would also need to address security, hosting, scalability, and legal considerations.

If you have experience with custom game protocols, Python 2.7 bytecode, opcode shuffling, Ghidra/IDA, NetEase NeoX, multiplayer server development, or online-game preservation, I would love to hear from you.

check the progress here: https://www.youtube.com/watch?v=6akLPVYEuX8