BRUTAL Goes Open Source: Ahwoo and RocketWerkz Release the Framework Behind RimWorld's New Engine

Free for commercial games, with no royalties: the C# framework behind Kitten Space Agency and RimWorld's Waylith Engine opens to developers worldwide.

AUCKLAND, New Zealand - 15 October 2026 - Ahwoo and RocketWerkz today announced the open source release of BRUTAL, a game development framework developed by Ahwoo in collaboration with RocketWerkz. BRUTAL is a free to use C# framework that developers can use to build a game directly or as the foundation for their own engine. This release gives teams an alternative to depending on a third-party engine, with access to the code they need to understand, modify and maintain their technology.

Ludeon Studios used BRUTAL to build Waylith, its new engine for RimWorld. In its announcement of Waylith and update 1.7, Ludeon reported performance improvements of two to four times in its tests. Ludeon used BRUTAL to help extract the last bits of Unity out of RimWorld to create their Waylith engine.

The framework currently powers six game projects across three studios, including RocketWerkz's Kitten Space Agency (KSA), which won the Most Innovative Hi-Tech Creative Technology Solution at the 2026 NZ Hi-Tech Awards. Judges praised KSA's simulation and graphics technology. RocketWerkz is also using the framework for other projects in development, including Art of the Rail and Torpedia.

At BRUTAL's core is a custom interop layer connecting modern C# and .NET to native APIs and high-performance C/C++ libraries, including Vulkan. Supporting libraries cover mathematics, memory management, job scheduling, logging and localization, with a focus on reducing allocations and unnecessary overhead. BRUTAL is free to use, including in commercial games, with no royalties or share of game revenue.

Felipe Falanghe, creator of Kerbal Space Program, is among the developers building with BRUTAL. His experience creating a spaceflight simulation and working through the limitations of its underlying engine informs his approach to the framework. Falanghe collaborates with RocketWerkz on Kitten Space Agency and is using BRUTAL for his next game.

"Coming from Unity to working in BRUTAL, initially it was a bit daunting," said Falanghe. "But once you're there, you own everything that you've created. You have full control and full knowledge of all of those things and how they operate."

RocketWerkz's experience with licensing reinforced the value of that control. In May 2025, RocketWerkz founder and CEO Dean Hall disputed a Unity notice threatening to revoke the studio's licenses, saying its evidence included two people who had never worked there. He told PC Gamer that the dispute validated RocketWerkz's existing move away from Unity for new projects.

"I'm not suggesting everyone should make their own game engine. I'm suggesting every developer should have the option to do so, without having to spend four years building the foundations first," said Dean Hall, founder and CEO of Ahwoo and RocketWerkz. "You are only as independent as your tools are."

BRUTAL is built for scale

A spaceflight simulation needs to track a spacecraft accurately while it travels across vast distances, approaches another vessel or lands on a planet. BRUTAL's development addressed challenges including the precision and scale required by Kitten Space Agency.

Meeting those demands required precise control over how positions are calculated and objects are rendered. BRUTAL allowed the team to design those systems around the simulation and investigate performance problems directly. The framework grew from a small collection of libraries over four years, with a deliberate focus on low-level functionality rather than adding the features of a general-purpose engine.

That control comes with responsibility, which is reflected in the framework's name. BRUTAL is intended for experienced programmers who want to make their own architectural decisions and are prepared to build and maintain the systems their games require.

"We called it BRUTAL because it can be brutal to use at times, and we wanted to be upfront about that," said Rian Drake, BRUTAL's Head of Engineering at Ahwoo. "We do not believe this is the tool that everyone should use to make a game. There are no guardrails. You're responsible for the systems you build and the mistakes you make, but you also have the control to put things right.

"When you hit a performance limit, you can get into the code, understand what's happening and change it. RocketWerkz's progress on Kitten Space Agency and Ludeon's work on Waylith for RimWorld show what a team can achieve with that freedom."

About BRUTAL

BRUTAL is a game development framework developed by Ahwoo in collaboration with RocketWerkz. It combines modern C# and .NET with C++ libraries and low-level graphics access to support games that demand performance, precision and scale. Learn more at ahwoo.com/brutal.

About Ahwoo

Ahwoo is a games platform and technology company founded by DayZ creator Dean Hall and based in Auckland, New Zealand. Its curated platform gives developers 85% of revenue and supports paid games, free releases and optional player contributions. Built to support games throughout their development and years after launch, Ahwoo brings updates, forums and support together so developers and players can connect directly. Ahwoo also develops BRUTAL in collaboration with RocketWerkz, giving teams greater control over the technology behind their games. Learn more at ahwoo.com.

About RocketWerkz

RocketWerkz is an independent, majority New Zealand-owned game studio based in Auckland, founded by DayZ creator Dean Hall. The studio makes survival and simulation games built on deep systems, strong technology and player feedback. Its titles include ICARUS, which has sold over 3.3 million units, Stationeers and Kitten Space Agency, with projects including Art of the Rail and Torpedia in development. RocketWerkz collaborates with Ahwoo on BRUTAL, the game development framework supporting its latest projects. Learn more at rocketwerkz.com.