A procedurally generated survival game with shitty graphics, which became popular because it was first-to-market and took advantage of nostalgia.
Unfortunately, Minecraft was never completed and the author fucked off with the money to make another game. Even with extraordinary success, the author didn't make good on promises and the game was never finished. (It would later be "finished" by having a recipe book concept and an "end".)
I loved this game, and even bought it twice to support the developer, but because it was Java it would bring a computer to its knees. Being sold out to Microsoft (for their upcoming virtual reality stuff I'd bet) was bafflingly insulting.
I would try it again years later, and it hasn't had basic improvements.