Here is the full list of all 20 Shadow Warrior Classic Redux achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Find 70 secret areas
Win 10 Pachinko games
Finish "Twin Dragon" expansion
Watch TV in Seppuku Station
Finish "Wanton Destruction" expansion
Finish "Code Of Honor" episode
Finish any level faster than 3D Realms time
Meet Sailor Moon
Hit 20 enemies with a vehicle
Defeat Sumo Demon boss
Fire Nuclear Missile
Collect 50 fortune cookies
Defeat Serpent God boss
Finish "Enter The Wang" episode
Find Monty Python and The Holy Grail reference
Kill 500 enemies
Slice 100 evil ninjas with Katana
Breed the rabbits to exhaustion
Use the Speed Racer RC car
Kill 50 enemies