Offset was more impressive back in the day because it was all graphics tech demo with no game behind it. Now they are building a game around it the graphics are getting scaled down more and more and coming back to earth.
It may be all perfectly doable, their scene is just a single street with some Background buildings as you can see in the video. As with any other tech demo, it looks great in small scale but probably wont be of much use in a game... unless you turn some options down and leave out some features... which probably will end up…