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