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