Here is the full list of all 28 The Hex achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Opened The Hex.
Completed ???'s memory.
Crashed Walk
Receive 4 card readings from Catarina in Walk.
Help Rebecha survive the first wave in Walk.
Free Vallamir.
Completed Lazarus' memory.
Wooed a Great Kraken.
Perform a 360 No Scope with the sniper rifle.
Discovered the truth about Mr. Shrewd.
Buy 10 upgrades from the Scrap Shop in Waste World.
Completed Rust's memory.
Crashed Waste World.
Activate a gated mod in Waste World.
Crack all the vending machines at The Six Pint.
Completed Chandrelle's memory.
Crashed Secrets of Legendaria.
Find Missing No. in Secrets of Legendaria.
Deal at least 500 damage in a single strike in Secrets of Legendaria.
Score a 1000 hit combo in Combat Arena X.
Score a true KO on Alley Gator in Combat Arena X.
Crashed Combat Arena X.
Complete the original Super Weasel Kid without any help from Mr. Shrewd.
Crashed Super Weasel Kid '09.
Learn all of Catarina's secrets in Super Weasel Kid.
Completed Bryce's memory.
Crack a soda vending machine at The Six Pint.
Completed Super Weasel Kid's memory.