Here is the full list of all 20 Alto's Adventure (Windows) achievements worth 1,000 gamerscore.
You snowboarded for five in-game years (cumulative). Way to go!
You recovered 100,000 llamas (cumulative).
you rode for 10,000,000m (cumulative).
You completed all 180 goals.
you recovered 10,000 llamas (cumulative).
You recovered 1,000 llamas (cumulative).
You rode for 100,000m (cumulative).
you rode for 1,000,000m (cumulative).
You played as Tupa.
You snowboarded for 365 in-game days (cumulative).
You played as Felipe.
You played as Izel.
You played as Paz.
You snowboarded for 30 in-game days (cumulative).
You rode for 10,000m (cumulative).
You played as Maya.
You snowboarded for seven in-game days (cumulative).
Your board stuck straight up after a crash. Oops!
You played one run with Alto.
You completed the tutorial.