Id say that this is the Perfect game for Creative Maniacs and simple game players.
The hing is: you also can put the difficulty to a point where no Monsters spawn, sounds boring, but the world of Minecraft (the one generated) will still give you enought threads to handle like damn deep cavers where you can get quite easily lost like in a natural grown labyrith or build Structures that make other players go Bwuah?
.
I like this game, somehow love it to have a Huge game world that gives me honestly EVERY F-ING Possibility and tells me: GO NUTS! Build Stuff or Burn down an Entire forest.
Heck! On one of my Levels I started to build up a small City close to my castle and ship (actually not working, you still get boats though, but it looks cool.
) or whatever you like.
As for a Sandbox game, if you wanna call it that way, it gives you yet the most freedom of all games yet seen I think.
@Badwolf14: Seemes like you played the fully Creativity mode where you dont have to harvest your stuff and cant die and such, thats for... just running wild in the Big Scale.