When a game is in alpha testing, it is just getting underway, and is not fully playable, and the only testing being done is done on a code to code basis to test as different codes are compleated.
Beta testing is when all components of the game are basically done, and it is just adding stylist stuff, and fixing bugs.
Public beta (if any) is just releacing the game to a large audiance for a short period to catch any last bugs and to see if any minor adjustments need to be made for the best result.
Blockland started out as a small toy that was done quickly, and when people took interest, Badspot decided to turn it into a full retail game.
Roblox has clearly passed any public beta, as it is making profit, and advertizing. It is at the same stage of blockland of being out, and having updates. The difference is that blockland has worked out its bugs, while Roblox has buggy product releaced, and is saying "It's all right because I'm not done yet"
