Here is the full list of all 22 1HEART achievements.
Complete the tutorial
Kill sheep
Pass the river
Enter the church
Get to basement without hints
Listen to four hidden tracks
Listen to seven hidden tracks
Make 200 mouse clicks
Make 2000 mouse clicks
Make 5000 mouse clicks
Solve ancient ornament riddle
Open door leading to the church basement
Check "The Pirate Bay" site in computer console
Check all console commands
Destroy all possible crates
Find all hidden hearts in the game
Solve hidden object puzzle without hint
Complete the game
Find dissecting room in less then 2 hours
Play 1Heart for one hour
Play 1Heart for more then three hours
Find half of the hidden hearts