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