Tetris was a pack-in game for a lot of Game Boys, so a lot of the sales could be attributed to that, although the game itself wasn't exclusive to the Game Boy, but on the other hand, it likely (as a standalone game) caused a lot of people to purchase one, as playing games on the move was quite a huge thing at the time of release, though nowadays, it's pretty much a given!
Of course, Tetris does have a much broader appeal than Minecraft (which I like), as it appealed to a lot of casual and non-gamers; it pretty much had the rare thing where anyone could pick up and play it, which is why it's so popular, and has seen multiple iterations. I'd put Tetris up there with Pong, as one of the most important video games in history.