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