BRUTAL

BRUTAL is the C# foundation RocketWerkz built Kitten Space Agency on, and the base Ludeon used for Waylith, the in-house engine moving RimWorld off Unity. It's a framework, not an engine: Vulkan, GLFW, SDL, Dear ImGui, Jolt and Box2D physics, FMOD audio and RakNet networking bindings, plus allocation-free collections, strings, memory and a job system. No editor, no scene graph, no renderer, by design. Free for commercial games, no royalties.

Install from NuGet (dotnet add package Ahwoo.Brutal.Core) on .NET 10, with a Vulkan 1.3 GPU if you render. The README says Windows or Linux; the homepage also lists macOS. You can't build from source yet: project files and build scripts are "coming." Hello world opens an empty window. Everything after that, renderer included, is yours to write.

There's no paid tier, but the license has a price: your credits, NOTICE.txt and the BRUTAL logo before gameplay, unless Ahwoo agrees otherwise. Solo devs: use Godot. Small studios with an engine programmer: worth a look. Larger studios outgrowing Unity: the real audience.

The catch: it went public this month. Open issues already report missing native exports in the Box2D and Jolt bindings, and FMOD may need a separate Firelight license.