The video was about a technical artist showing what you can do with the
UED (Unreal Editor) 4.
Everything in the video looks very promising, but what caught me the most is what happens at the end of the video (at about 9:40). The guy showing the engine opens Visual Studio from within the UED and changes some c++ code (in the video he's manipulating the player's jump height).
When he returns to the game a little message appears saying "Compiling C++ Code...".
After a few seconds a new message appears saying "C++ Code successfully compiled".
After that he was jumping twice as high as before.
This is IMO one of the most astonishing things I've ever seen. In that way you could use C++ as a scripting language...A very powerful one.
I have absolutely no idea how they've implemented that, but that feature is just amazing and I'm eager to find out how that works ;).