Here is the full list of all 12 Karateka achievements.
Defeated the bully on the bridge
Reached the palace garden
Reached the palace gates
Earned the respect of a brother monk
Rescued Mariko from the evil warlord Akuma
Rescued Mariko as the Monk
Rescued Mariko as the True Love
Surmounted the Great Wall without getting hit once
Defeated Akuma without collecting any of Mariko's flowers
Challenged Akuma, untouched by his minions
You reached the Bamboo Forest in under 6 minutes
Rescued Mariko in under 30 minutes