At its heart, Minecraft is a blocky first-person game about building things, exploring an endless wilderness, and fighting off nasty nocturnal beasts, but that doesn't do it justice. Minecraft is to my 25-year-old self as Legos were to my 5-year-old self: a time-sucking, mind-bending, and sleep-depriving experience in the simplest of activities. It hits the right tune on the subject of creation: it really does provide building blocks for your imagination.
Minecraft has no real direction, anchoring plot, or specific guidelines. Players are dropped into a world with only the ability to carve out resources from the surrounding land; you're a miner (duh!).
The game's graphics won't impress, but leaves you with one direction and focus: to build. Soon you'll find out that as it gets dark, chilling around with a pickax probably won't do you any good against the pixelated zombies, monsters, and other creepy critters after you.
Minecraft's central focus is in crafting tools and collecting resources to pretty much build whatever you want. Whether it's building more-powerful weapons to fend off creatures of the night or building that mega fortress to gloat at other miners in the open world, you're still going to need the right raw materials. Make no mistake: this game is a grinder. But after toiling for hours and hours and finally stumbling upon that precise material you need is a priceless moment in its own right.
As a self-sustaining teacher, Minecraft fails. Don't rely on Majong's limited provisions to learn the ropes of the game. Instead, I recommend scouting the Net for community made guides: there's a plethora of custom guides out there that will help you get the most out of this game. And really, that limit is all up to you.
If you simply want to focus on building and avoid the hassle of defending your fortress, then Creative mode is for you. In this mode, you have unrestricted access to all the building blocks and tools needed to build the structure or statue of your dreams, plus the ability to fly for kicks.
If you're uncomfortable with lack of direction, then this game isn't for you. But when it comes to open-world gameplay and mechanics, Minecraft is a primitive but fine demonstration of thriving on bare-bones gaming. Grab an ax and start digging.