Castle Game Engine vs Flax Engine
Castle Game Engine
castle-engine.io
Flax Engine
flaxengine.comSide by side
| Figure | Castle Game Engine | Flax Engine |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | Yes | Yes |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| iOS | Yes | Yes |
| Android | Yes | Yes |
| Plans published | 1 | 2 |
| Spec score · Game Development Software | 8.6 (#12) | 8.8 (#7) |
| Spec score · Game Engine Software | 8.2 (#50) | 8.9 (#10) |
| Free plan | Yes | Yes |
| Mobile export | Yes | Yes |
| Networking | Networking features include asynchronous URL downloads and integrations with Indy, mORMot 2 and RNL. | The engine provides low-level and high-level networking APIs for multiplayer games. |
| Rendering | Graphics features include shader effects, physically based rendering, shadows, mirrors, bump mapping and post-processing. | The feature set includes realtime global illumination, reflections with custom software ray tracing, and GPU lightmap baking. |
| Scripting languages | Object Pascal (Free Pascal/Lazarus) | C#,C++ |
| Source code model | open_source | source_available |
| Support | The maker invites questions and feedback on its forum and offers meetings with the engine lead to discuss use, bugs, feature requests and cooperation. | The feature page promises direct communication and help from engine developers, and the site provides a contact form. |
| Target platforms | Windows,Linux,macOS,Android,iOS | Windows,Linux,Android,iOS,PlayStation 4/5,Xbox One/Series,Nintendo Switch |
Plans
In their own words
Castle Game Engine
Castle Game Engine is a free, open-source engine for building 2D and 3D games with a visual editor and an Object Pascal API. The editor supports designing game worlds and interfaces, then building projects for multiple platforms. Listed targets include Windows, Linux, macOS, Android, and iOS, with mobile export, console export, and multiplayer tools. Graphics capabilities include shader effects, physically based rendering, shadows, mirrors, bump mapping, and post-processing. Supported formats include glTF, X3D, sprite sheets, and Spine 2D animations. The project lists Visual Studio Code, Lazarus, Delphi, Blender, and Sketchfab among supported tools and services. A command-line build tool, Docker image, and CI setup documentation support automation. The engine can be used for proprietary applications. Provided Linux binaries require GLIBC 2.34 or newer; older systems can compile from source. Supported operating systems must still receive vendor security support, with Windows 10 temporarily supported as of 2026.
Flax Engine
Flax Engine is a 3D game engine written in C++ and C#, with visual scripting and full Editor source code available. It supports C++, C#, and visual scripting, with hot-reloading for both programming languages in the Editor. Rendering features include real-time global illumination, reflections using custom software ray tracing, and GPU lightmap baking. World-building tools cover terrain, foliage, fog, nested prefabs, level streaming, and large-world 64-bit coordinates. Multiplayer projects can use low- and high-level networking APIs. Its Online system supports services such as Steam, Xbox Live, and PlayStation Network for profiles, friends, achievements, presence, and cloud saves. Supported targets include Windows, Linux, Android, iOS, macOS, web, PlayStation 4 and 5, Xbox One and Series, and Nintendo Switch. Web support is experimental and lacks C# scripting, video playback, and some other engine features. NDA-protected platform support is excluded from the public repository. The engine is free for non-commercial or educational use; commercial releases pay a 4% royalty on earnings exceeding $250,000 per calendar quarter.