Here is the full list of all 19 Sproggiwood achievements.
Beat a dungeon without killing any enemies besides the boss.
Beat the game on Savage with every class.
Beat Uppmas Point on Savage with every class.
Beat the Floating Isles on Savage with every class.
Beat Ensi on Savage with every class.
Beat Ignis Caverna on Savage with every class.
Beat Hakkipunki on Savage with every class.
Beat the Bloated Grotto on Savage with every class.
Kill 10 enemies in one turn.
Beat Big Tree on Savage with every class.
Beat Goaturku on Savage with every class.
Beat Ickykolo on Savage with every class.
Defeat Surma on Normal.
Defeat Surma on Easy.
Kill a monster that loves you.
Kill 5 enemies in one turn.
Kill a bizarro cloghead.
Defeat Big Ick on Easy.
Defeat Big Ick on Normal.