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
Burn 4 monsters with one bottle
Complete all three episodes
Complete episode 3
Give a gastroscopy
Kill or damage 10 monsters with landmines
Find Tuzex vouchers
Find a postcard from the creators of Project Warlock 2
Complete 6 different levels on Very High Difficulty
Have a gastroscopy
Kill a monster by knocking it off somewhere high with the footkick
Hit the enemy with a kicked grenade
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
Get past wave 15 in Endless Mode
Run over 10 monsters
Get past wave 10 in Endless Mode
Survive wave 5 in Endless Mode
Complete episode 2
Clean all mess after the Degustation
Find all plates in the Granny's Valley and bring them to the Degustation
Anger the bees and run away
Kill 35 monster types
A lot of wine
Start the mining train
Gottwald's body missing
Complete episode 1
Kill Headsman in air during jump
Find 50 different secrets
Discover a secret of Vyšehrad Castle
Gib a horse
Kill 500 monsters in total
Hit an enemy with the soccer ball
Achieve a score of 200 points on a handheld game
Find a second pistol
Find all secrets in a level
Kill all monsters in a level
Get through a level without damage
Kill 5 monsters with a sickle in a row without damage