Rainway is game streaming. We take the game running on one system (say your home PC) and stream it to the other device. You can read about the tech here: https://rainway.io/technology/
BTW latency still matters here, so an even awesomer future "Show HN" might include some great analysis on how you got your product from X ms peak latency down to Y ms peak latency.
Can I use it to stream the display to another system, but continue using the mouse and keyboard from the gaming PC?
I want to see my PC game on my Mac, but my gaming PC has way better input devices for gaming. (My gaming PC is near my Mac...it is just that the way my desktop is arranged the PC monitor is in a place that is not good for long term viewing, but I can easily put the PC mouse and keyboard in front of the iMac).
Also, it wasn't quite clear from your site. Does this only work with games that you have to specifically include support for, or is it more general?
You could, yes. We don't take over the controls and simply pass input to the system mouse and keyboard or to the controller we emulate on the machine. So you could stream to your mac and play using your PC's keyboard and mouse.
It works with all games you own through all digital game sellers.