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