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
Complete all three episodes
Complete episode 3
Give a gastroscopy
Complete 6 different levels on Very High Difficulty
Find a postcard from the creators of Project Warlock 2
Kill a monster by knocking it off somewhere high with the footkick
Burn 4 monsters with one bottle
Kill or damage 10 monsters with landmines
Find Tuzex vouchers
Hit the enemy with a kicked grenade
Have a gastroscopy
Surprise the newt in the cabin
I really like this random stuff
Early Access sauna is a cold place
Shoot down a flying pigeon
Free 4 Ratters
Locate the secret level
Pet two dogs
Waste three minutes watching the model railway
Kill 35 monster types
Get past wave 15 in Endless Mode
Find 50 different secrets
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
Achieve a score of 200 points on a handheld game
Get past wave 10 in Endless Mode
Survive wave 5 in Endless Mode
Get through a level without damage
Kill Headsman in air during jump
Gottwald's body missing
Discover a secret of Vyšehrad Castle
Find all secrets in a level
Kill 5 monsters with a sickle in a row without damage
Start the mining train
Complete episode 1
Kill 500 monsters in total
Gib a horse
Run over 10 monsters
Hit an enemy with the soccer ball
Find a second pistol
Kill all monsters in a level