Here is the full list of all 27 OXENFREE II: Lost Signals achievements.
"...the apex of my accomplishment."
Become friendly with Charlie.
"Finally...Planetshine."
Don't pet Athena.
Discover all Adler letters.
Talk to a young radio enthusiast.
Deliver the shoe to Hank.
Hear Maria tell Charlie she has a crush on him.
Agree to be a special kind of friends.
Prevent Olivia from tuning the portal and smash her radio.
Prevent Olivia from tuning the portal in any way.
Create the scariest One Word Story.
Become friendly with Olivia.
Become friendly with Violet.
"...accept what you find."
Pet Athena.
Finish Nick’s journey.
Check in with Evelyn for all three transmitters.
Place the transmitter at Garland.
Discover the complete Adler Letters Set 2.
Save Shelley.
Discover the complete Adler Letters Set 4.
Place the transmitter at Tootega Falls.
Discover the complete Adler Letters Set 1.
Place the transmitter at Charity Point.
Discover the complete Adler Letters Set 3.
Find out the secret at Jacob's House.