It looks like the included demo was written in LUA, unless I'm missing something, so that's too bad.
I've been looking for a reason to learn C++, and apparently this engine supports it, so I will be using it for a few days. Driving through the river was quite impressive because it creates waves as you drive along. In the demo you will find a fork in the road, the left side takes you to a testing area, the right side takes you to a river. It was impressive to see the tires deforming on the rocks, and the mud getting dug up as I got deeper into it. The only way I was able to play it was through a torrent on The Pirate Bay. Based on what I can find, this demo was made for a Kickstarter campaign.
I looked around, but all the links to download it are dead. You might want to take a look at the demo called 'SpinTires'. I could see this as being something that could compete with Unity. I've taken a look at this new engine, it's really quite impressive.