Here is the full list of all 21 MewnBase achievements.
Complete 10 missions
Complete an Only Night mission
Complete a Long Night mission
Research 100 artifacts
Collect 250 plants grown in a Garden Patch or Greenhouse
Craft 500 metal plates
Construct your 100th Habitat Modules
Complete your artifact research log
Have a base that has over 1000 water stored
Repair 100 air leaks
Have a base that generates over 200 power/sec
Survive for 50 days
Unlock all tech upgrades
Complete your first mission
Survive for 25 days
Build a buggie!
Collect 10 plants grown in a Garden Patch or Greenhouse
Unlock 5 tech upgrades
Construct a Habitat Module
Unlock 1 tech upgrades
Research 1 Artifact