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