I got Minecraft (Alpha) yesterday. I played for a few hours. I made a castle, a dungeon, and a house. I realized that's pretty much what the entire game was. It's like Legos, but slower and you can kill stuff. If you're thinking about getting it, the free version is almost exactly the same. The weapons/enemies don't really add anything to the game. Don't waste 9.95 Euros on it.
Well.... Dwarf Fortress is win. Better gameplay, more brutal fighting, WAY better community, HUGE mods, accessible modding, free, better updates, more monsters, dying in far more fun ways, better history, and the upcoming necromancy & curses update is going to blow peoples minds.
Imagine a dog runs at the necromancers. The dog gets killed, head hacked off. A headless zombie-dog runs back at the defenders. And were-creatures. They are win.
And Adventurer mode with DFhack is awesome, jumping between modes like anything. And controlling a little fort, which Minecraft cannot do. Overall, DF is more realistic, more buildy and just more violent.