Here is the full list of all 55 HROT achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Check the simulator
Surprise the newt in the cabin
Kill a monster by knocking it off somewhere high with the footkick
Find Tuzex vouchers
Find a postcard from the creators of Project Warlock 2
Discover a secret of Vyšehrad Castle
Free 4 Ratters
Locate the secret level
Complete all three episodes
Complete episode 3
Give a gastroscopy
Pet two dogs
Waste three minutes watching the model railway
Early Access sauna is a cold place
Shoot down a flying pigeon
Have a gastroscopy
I really like this random stuff
Kill 35 monster types
Hit the enemy with a kicked grenade
Find all plates in the Granny's Valley and bring them to the Degustation
Complete episode 2
Clean all mess after the Degustation
Anger the bees and run away
A lot of wine
Find 50 different secrets
Burn 4 monsters with one bottle
Get through a level without damage
Start the mining train
Kill Headsman in air during jump
Get past wave 15 in Endless Mode
Gottwald's body missing
Kill or damage 10 monsters with landmines
Complete 6 different levels on Very High Difficulty
Gib a horse
Achieve a score of 200 points on a handheld game
Kill 500 monsters in total
Hit an enemy with the soccer ball
Kill all monsters in a level
Kill 5 monsters with a sickle in a row without damage
Get past wave 10 in Endless Mode
Survive wave 5 in Endless Mode
Run over 10 monsters
Complete episode 1
Find all secrets in a level
Find a second pistol