Here is the full list of all 18 Karate Master 2 Knock Down Blow achievements.
Requires KI 10
Requires speed 10
Requires tai kitae 10
Win the Kumite tournament.
Jump over a car.
Win a ring event.
Requires toughness 10
Defeat Oboro.
Defeat the legendary Sensei Matsu.
Reach fame 100.
Win a Karate-Pro tournament.
Requires strength 10
Heal yourself in the hospital.
Win a Bogu Kumite Tournament.
Win a Full Contact Karate tournament.
Defeat the bull.
Defeat the bear.
You need to earn 1500 bucks.