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