I think I know what game you mean there
Best Showcase for Next Gen
In the week that Fallout 4 was released looking like a last-last-gen game, I think the best showcase I have seen this year was Dying Light
for PS4. Yes, the zombie game from the Dead Island guys. I was tremendously impressed with this - there were literally no technical issues, no screen tearing, a massive world with no loading screens, and the world was enormously diverse as regards buildings, textures etc. Either that, or their use was incredibly cunningly disguised...which I am sure was the case.
It was an amazing achievement, having a world you could run through at high speed, parkouring all the way, with no issues whatsoever.
The game itself was really good, but about 70% too long, a personal issue I suppose.