Here is the full list of all 21 Scrap Garden - The Day Before achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Finish the game
Beat the Boss!
Find the Engineer
Break into the computer.
Eliminate 10 enemies
Fix the water pipes
Collect 300 spares
Collect 100 spares
Jump into the water
Break 10 boxes
Collect 50 spares
Collect 10 spares
Start the game
Collect 500 spares
Eliminate 50 enemies
Eliminate 100 enemies
Break 50 boxes
Break 100 boxes
Find something in the collector
Finish the game without being damaged
Find old arcade machine