Here is the full list of all 42 Flotsam achievements.
The base game contains 0 achievements, and there is 1 DLC pack containing 42 achievements.
Rescue the Aquaculturist.
Rescue the Architect.
Rescue the Birdkeeper.
Rescue the Botanist.
Rescue the Chef.
Rescue the Doctor.
Rescue the Electrician.
Rescue the Chemist.
Rescue the Engineer.
Rescue the Farmer.
Rescue the Radio Technician.
Rescue a drifter.
Research all technologies.
Build a Salvaging Boat.
Have a town with 10 drifters.
Have a town with 25 drifters.
Reach day 100.
Travel 50.000 units with the town.
Travel 200.000 units with the town.
Rescue 10 seagulls.
Travel 42.000 units within 80 days.
Have more seagulls than drifters in your town.
Complete the game without having a drifter die.
Survive 20 days with all drifters eating only Seaweed Salads.
Have 10 or more ecstatic drifters at the same time.
Survive 20 days with a single drifter.
Have 50 or more buildings upgraded with Gas Bags.
Cook 50 'Yummy' or higher quality food in a single day.
Craft 100 'Animal Chow' in a single day.
Generate over 150 Eels/s by only using Manual-Powered Generators.
Have 15 or more drifters doing their favorite task at the same time.
Have a drifter with maximum expertise in all attributes.
Reach day 365.
Survive 30 consecutive days without cooking food.
Use a total of 100 Fresh Water in a single day.
Exceed 15.000 total weight of the town.
Fully salvage 15 different landmarks in one day.
House all drifters.