Here is the full list of all 63 Sly Slime achievements.
Level 61
Final
Level 60
Level 59
Level 58
Level 57
Level 56
Level 55
Level 54
Level 53
Level 52
Level 51
Level 50
Level 49
Level 48
Level 47
Level 46
Level 45
Level 44
Level 43
Level 42
Level 41
Level 40
Level 39
Level 38
Level 37
Level 36
Level 35
Level 34
Level 33
Level 32
Level 31
Level 30
Level 29
Level 28
Level 27
Level 26
Level 25
Level 24
Level 23
Level 22
Level 21
Level 20
Level 19
Level 18
Level 17
Level 16
Level 15
Level 14
Level 13
Level 12
Level 11
Level 10
Level 9
Level 8
Level 7
Level 6
Level 5
Level 4
Level 3
Level 2
Level 1
Level 0