I've wanted them to do this for years, and I know I'm not the first person to think of it. I wonder what made them decide to finally try out a user experience like this.
There are a bunch like this. Try "recursion", "the answer to life, the universe and everything", "tilt", "barrel roll", "kerning" (and "keming"), "google pacman", "zerg rush", or "conway's game of life".