Here is the full list of all 25 Gothic Playable Teaser achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
Finish the game.
Completed - The Fire Signal.
Completed - Some Meat as a Debt.
Kill 1 snapper.
Completed - A Well Deserved Break.
Barely survive a fall.
Completed - Medicines for Sarus.
Kill 5 scavengers.
Completed - A Decent Sword.
Collect 20 blueberries.
Kill 6 wolves.
Build someone's trust in the Colony.
Crush 10 meatbugs.
Open 3 locked chests.
Collect 10 coins.
Completed - Orry's Headache.
Loot a human body 3 times.
Survived the first night in the Colony.
Get your first weapon.
Heed nature’s call.
Prepare three different cooking recipes.
Get your first magic item.
Collect 15 ore nuggets.
Investigate to the end a hidden mistery.
Start a confrontation between creatures.