Here is the full list of all 33 Midsummer Night achievements.
Complete the game
Listen to the story to the end
Discover Dead Forest secret
Climb up the hill
Spend two hours in the game
Take 9 attempts to pass one of challenges
Exit kremlin underground by the sound of the stream
Reveal bear's secret
Get to the Flooded island by water
Encourage peasants to change their attitude toward village elders
Wait out an ancient deity awakening in a hidden place
Cross the swamps
Take 3 attempts to pass one of challenges
Find the trail of the beast
Step on a frog 3 times
Give strength to the frog
Spend one hour in the game
Spend 30 minutes in the game
Find caves in the forest
Collect antidote
Punch a one-eyed likho 3 times
Examine 4 sorts of flowers using Q key
Find the dugout in the forest
Help the ghost find his parents
Help the Apple Tree
Exit kremlin underground through the Red Chamber
Get to the Flooded island by underway
Use squirrel to get the boat
Reveal Man's name
Cross the river over the log
Pull the merchant out of the swamps
Save the baby from starvation
Get even with the bear