Valve’s sudden entry into the engine race, with an official announcement of Source 2, seems to have put them right up front alongside frenzied rivals Unity and Unreal. (Poor old Crytek, eh?) Meeting with studio founder Erik Johnson today, I learned that when they say Source 2 is “free”, they mean it. Unlike Unity’s (much lowered) subscription rates (for larger teams), and Epic’s revenue cut of successful projects, Valve won’t be asking for any money at all. Well, sort of… They just require that the game be launched on Steam, along with anywhere else you might want to sell it.

That’s pretty huge. But it’s important to point out it’s also pretty smart. In real-terms, it does mean Valve are going to be getting – in fact – 30% of your revenue, as is standard for anything sold on Steam. However, and crucially, developers are going to be free to also sell their game anywhere else, which means you can also use stores that take far lower cuts. Use Source 2, put your game on Steam and take advantage of Steamworks, the community features, and so on, but direct all your customers to your Humble store where only see 5% won’t reach you.

-http://www.rockpapershotgun.com/2015/03/04/source-2-is-actually-free-like-for-free/