Here is the full list of all 19 Obscure II Obscure: The Aftermath achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Finish the game.
Open all of the chests.
Jedidiah won't make any more trouble.
Obtain every available weapon during a game.
Get to the main yard at Leafmore.
Prepare a serum, an improved serum and a powerful serum.
Find Sven.
Consume 10 energy drinks.
Get to Jedidiah's house.
Find Amy at the Fallcreek dam.
Heal a teammate 10 times.
Go through the hospital.
Find Jun.
Find Corey's car and get to the hospital.
Recharge electric weapons 10 times.
Meet up with Kenny and Amy at the Delta Theta Gamma party
Go to the Delta Theta Gamma party.
Open a chest.
Over-consumption of tea is not recommended.