Here is the full list of all 20 Telmari achievements.
You have completed the tutorial.
Meet the dodo for the first time.
Died to spines for the first time.
You have convinced the ill tempered Ancient One to accompany you.
First death.
You have died ten times.
You have died a hundred times.
You beat the Ancient One for the first time.
You beat the Ancient One ten times.
You beat the Ancient One twenty times.
You beat the Ancient One fifty times.
You beat the cat in all 105 levels.
Bounce on a three plunger arrows.
Bounce on four plunger arrows.
Finish the forest.
Finish the mountain.
Finish the desert.
Complete all levels.
You receive all achievements.
You have died a total of fifty times.