Here is the full list of all 100 101 Cats Hidden achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
95
98
60
56
42
27
70
44
26
31
68
79
94
76
81
83
30
93
66
82
96
86
84
45
92
50
38
33
58
41
85
87
53
90
48
100
65
97
10
17
61
57
88
89
78
37
99
18
54
64
32
73
34
20
35
36
9
91
72
15
2
13
1
59
7
6
12
24
77
3
8
47
49
55
43
11
71
67
5
51
25
74
16
69
23
63
22
29
40
52
46
39
21
14
75
19
62
80
28
4