Check out Notch's Twitch broadcast history[1]. Since Mojang was sold he has been playing a variety of games, but scroll down a bit and it mostly turns into live programming and Team Fortress 2.

1. http://www.twitch.tv/notch/profile/past_broadcasts

The earliest broadcast is titled "Notch: Creator of Minecraft," from August 2011. Minecraft was released in 2009. So those videos aren't really evidence one way or the other in regards to what I'm saying: people who do big solo projects don't seem to play many games during the time they're hammering out features. And while Notch's LD sprints are impressive, he hasn't really shipped a big project since Minecraft.

Whoops, I just noticed I phrased my original comment like "I wonder how many games Notch plays" (present tense) which is exactly what you showed. I meant to phrase it in past tense. Sorry, that was my bad.

Notch had handed over the vast majority of Minecraft development to Jeb at that point so its not surprising that he was playing so much TF2. I doubt he was playing as much when he was the sole developer.