Here is the full list of all 15 Risk of Rain achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Deal 5000 damage in one shot.
Find the robot janitor.
Bank 20,000 gold.
Survive 40 minutes.
Kill the Magma Worm, Wandering Vagrant, and Giant Stone Golem.
Fail a shrine 3 times in a row.
Pass a shrine 4 times in a row.
Defeat 20 lemurians in one playthrough.
Kill a boss with 'Lights Out'.
Find the bloated survivor.
Collect 15 Monster Logs.
Unlock a golden chest with the Explorer's Key.
Die 50 times.
Drown 20 Whorls.
Collect 4 Keycards.