Here is the full list of all 15 Crocogame achievements.
Beat toxic sewers
Beat Ice Ruins
Beat Ancienct Crypt
Beat the game without taking any damage
Beat the game with all crocos
Beat the game at +1 difficulty
Beat the game at +2 difficulty
Beat the game at +3 difficulty
Beat the game at +4 difficulty
Beat the game at +5 difficulty
Beat the game at +6 difficulty
Beat the game at +7 difficulty
Beat the game at +8 difficulty
Beat the game at +9 difficulty
Beat the game at +10 difficulty