Here is the full list of all 11 Telmari Demo 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 total of fifty times.
You beat the Ancient One for the first time.
You beat the Ancient One ten times.
Bounce on a three plunger arrows.
Bounce on four plunger arrows.