Don't know why this is downvoted. The turnaround time for a functioning tetris game is very quick, within a day (even if you don't know the tools yet). This one isn't even a functioning tetris game, it's basically just a physics simulation (probably using an existing library) with very simple rules that are activated upon collision.
I'm not suggesting that this is The Technological Achievement of Our Age (TM), only that it's impressive that two days after the posting of a webcomic, that the comic's theme has been actualized. Tetris isn't a hard problem, and this almost certainly used a physics library, but it's impressive and amusing nonetheless.
Maybe I'm easily impressed, but I think it's neat.
