The game "Rust" uses the Unity game engine. Unity is a popular game development platform used by many developers due to its powerful features and flexibility.
The creators of Rust, Facepunch Studios, utilized Unity's robust toolset to create their survival-focused multiplayer experience. Unity can handle both 2D and 3D graphics, has cross-platform capabilities, and supports various scripting languages, which makes it suitable for a wide range of game types.
Here is an example of how you might start a basic Unity project (though not specifically related to Rust):
Even though Unity provides a large set of tools that can help with developing games, it's important to note that the implementation details specific to Rust would involve proprietary code created by Facepunch Studios to provide the unique gameplay elements seen in the game.