Here is the full list of all 12 Minesweeper Extended achievements.
You got your first Win!
You got you first Loss!
You've won 10 times!
You've won 50 times!
You've won 100 times!
You've cleared the smallest board size!
You've cleared the largest board size!
You won without using any Flags!
You won without using any.. mines?
You beat a game in under 5 Minutes!
You beat a game in under 2 Minutes!
You beat a game in under 1 Minute!