Full list of all 19 Leap Year achievements. It takes around 1-2 hours to unlock all of the achievements in the base game on Windows.
The base game contains 12 achievements, and there is 1 DLC pack containing 7 achievements.
[March DLC] Collect the first 30 days of March
[March DLC] Collect the last day of March
[March DLC] Beat March in under 45 minutes
[March DLC] Beat March in under 30 minutes