Here is the full list of all 10 Magic Potion Explorer achievements.
Cleared NORMAL Mode
Get to B50F with less than 20000 Max HP
Get to B50F with less than 200000 Max RP
It started for the first time.
Cleared NORMAL Mode at S Rank
Cleared HARD Mode
Cleared HARD Mode at S Rank
Finished without being defeated once
Took an attack from the boss on B50F
Took an attack from the boss on B99F