Survival, Classic, Beta? What is Minecraft Alpha?
Minecraft Alpha encompasses all the changes to the game so far, as well as all the alterations and additions before it. Specifically, Alpha is not Classic or Creation Mode, but currently it is what we know as Survival Mode, or the bulk of the single player experience. To those unfamiliar with these terms, the "Alpha" in Minecraft Alpha is merely a name for this specific build of the game. Game 'builds' are much like how car companies all sell the same sort of cars, but each new version has a different name. (They all have four tires, doors, and an engine. Would get a little complicated and confusing if they do not name them something specific, right?) The preferred method of naming game builds are based upon the Greek alphabet (Alpha, Beta, Gamma, and so on). Thus, the first build is Alpha, as Minecraft Alpha clearly shows what build the game is currently in, and why the next build will be Beta. After that happens, instead of Minecraft going Gamma, the game is considered "retail" or "released" and has 'launched.' From that point on, every version of the game will drop the Greek and will only use numbers, which is a whole article in itself.
What Changes from Minecraft Alpha to Minecraft Beta?
At first…not so much. Minecraft Alpha ends the moment Beta begins. (The whole Greek bit is mostly semantics, but still helpful.) Every change to Alpha is a change to Beta, and to most players they will not even know the difference until Notch adds something big, like the Halloween update in October (of all times to release a Halloween-based change!). The end of Alpha is being paved with changes to the Survival Multiplayer aspect of the game. Fans who only play single player will not be affected by this transitional period until the changes made to the game begin to affect single player directly (most likely after Beta is live, or 'activated'). In a more general sense, games in Alpha are considered buggy and just barely playable, while Beta (being closer to Release), is more stable and crashes less. Minecraft is one amazing game in more ways than one, but especially in this regard. For any game this early in development, let alone such an indie sensation mostly made by one lone guy, it is remarkably stable already, but Beta will likely improve upon its strengths even further.
When Will Alpha End?
According to Notch's development blog, in less than ten days. December 20th will be the last day of Minecraft Alpha, ushering in a new build to the game, as well as a new, higher, price. If you are still on the fence, I'd recommend deciding soon. All those who purchase before Beta will not only get the same game cheaper, but also get every future update free of charge. All those who wait? Not as lucky. Not only will the cost of the game increase by at least fifty percent, but every time the game is updated it will cost as well, unless you purchase before Beta begins. All those who have the game before Beta will not have to pay for every update, as a form of thanks for supporting the game during it's early development.