Article taken from GamingOnLinux.com.

The C4 Engine is a comprehensive suite of robustly implemented game programming tools for the Windows, Mac OS X, Linux, PS4, and PS3 platforms.A reader pointed this out to me some time ago but it kept getting pushed back on my to-do list, no more!The C4 Engine is a comprehensive suite of robustly implemented game programming tools for the Windows, Mac OS X, Linux, PS4, and PS3 platforms. Not only is it a powerhouse of a 3D graphics engine, but it also includes integrated support for physics, audio, networking, input devices, resource management, and much more . The C4 Engine is widely regarded as having the cleanest professional source code and one of the best architectures in the industry.So this engine looks pretty awesome, for comparison it's pro version costs the same as Unity's but it's more expensive than Leadwerks, C4's editor runs on Linux (Unity doesn't) and it actually exists (Leadwerks for Linux doesn't yet).The icing on the cake is that even the standard version gives you the full source code!It has too many features to list , I really suggest you check it out if you want to make games.Here is an example video:To note: This demo games full source code is included with the cheapest version.Which brings me onto this: The 31st Haunted is being made by the C4 Engine developers as a full game and will support Linux, awesome. What better way to show off an engine you made for developers than to make a full commercial game with it yourselves?