Here is the full list of all 20 HIDEAWAY achievements.
Find a Sleeping Poison for the first time.
Find 15 Sleeping Poisons.
Find 30 Sleeping Poisons.
Find 50 Sleeping Poisons.
Snatch a Skull for the first time.
Snatch 15 Skulls from the Cryptid.
Snatch 30 Skulls from the Cryptid.
Snatch 50 Skulls from the Cryptid.
Put the Cryptid to sleep for the first time.
Put the Cryptid to sleep for the 15th time.
Put the Cryptid to sleep for the 30th time.
Get caught for the first time.
Get caught 15 times.
Get caught 30 times.
Put a Skull to the Snow Altar.
Place the final Skull on the Snow Altar.
Place Skulls at Snow Altars for 15 times.
Stay 10 minutes outside of Cabin and resist cold exposure.
Stay 20 minutes outside of Cabin and resist cold exposure.
Stay 30 minutes outside of Cabin and resist cold exposure.