Here is the full list of all 33 Isekai Janken Hero achievements.
Cleared the 1st Cattia stage
Cleared the 2nd Cattia stage
Cleared the 3rd Cattia stage
Cleared the 4th Cattia stage
Cleared the 1st Minos stage
Cleared the 2nd Minos stage
Cleared the 3rd Minos stage
Cleared the 1st Gekka stage
Cleared the 2nd Gekka stage
Cleared the 3rd Gekka stage
Cleared the 1st Sylph stage
Cleared the 2nd Sylph stage
Cleared the 3rd Sylph stage
Cleared the 1st Verdi stage
Cleared the 2nd Verdi stage
Cleared the 3rd Verdi stage
Unlocked a story branch
Reached the Bad End
Reached the Happy End
Achieved Max Attack
Achieved Max Guard
Achieved Max Heal
Achived Max HP
Hit the Janken Indicator target 20 times
Won 50 matches
Used Attack 100 times
Used Guard 100 times
Used Heal 100 Times
Cattia used Rage once
Minos used Rage once
Gekka used Rage once
Sylph used Rage once
Verdi used Rage once