Here is the full list of all 31 Gatekeeper achievements.
Visit the planet Aridune in normal mode.
Kill 25 Hermits without letting them open the shell.
Use only the second skill during the fight with Siren.
Ignite more than 20 enemies at once.
Kill 10 enemies with one hit.
Complete 20 rounds in the Arena.
Reach a health level of 500.
Activate Quorium without using skills during the mission.
"Kill them all" in 100 seconds.
Pass the planet while maintaining continuous movement.
After taking no damage from the Siren, deal a fatal blow to it.
Collect more than 20 of the same artifact.
Pass the first planet without evolving.
Find Juju.
Pass a location without taking health or shield damage.
Activate all Cell of the Ancients monoliths in 10 seconds.
Kill any Siren in 30 seconds.
Deal over 5 million damage in one run.
Kill any enemy while having less than 10 HP.
Destroy all available artifacts in the forge, after a 60 minute run.
Die at the first location.
Die within 2 seconds at full health.
Die while selecting an artifact.
Deal a fatal blow to Siren and die within 7 seconds of its death.
Die at the hands of an enemy with less than 5% health.
Die in the 42nd minute of the run.
Visit the planet Aurora twice per run.
Pass a total of 60 locations.
Activate the capsule with Echo.
Activate Apotheosis.
Find Dawnbreaker.