You can get the latest update at www.quad-engine.com.
There is also online documentation in English that will tell you the latest changes to Quad-Engine right here.
Quad-Engine "Galaxian" Remake Demo Video
So far there are a couple of games made with the fairly capable Quad-Engine. Such games are still in development by Darthman of IGDC fame himself, but include two called Void Story and a newer one called Rusty War. Their websites are in Russian so Google Translate or Alta-vista's Babelfish might come in handy if you are curious about them.
Information about both projects is fairly limited due to most information being in Russian and that they are in early development. I'm sure that we will hear much more about these exciting projects as some form of beta or demo comes available.
Terrain Test Demo for Void Story
Check out his collaboration with Poets of The Fall on Void Story at www.voidstory.com.
Check out his collaboration with Lionwood Studios on Rusty War at www.lionwoodgames.com. The game has it's own website at www.rustywar.com.