Here is the full list of all 31 Hidden Office achievements.
All levels completed
Russian Blue 3
Maine Coon 1
Siamese 3
Somali 3
Sphynx 2
Maine Coon 2
Siamese 2
Snowshoe 3
Persian 3
Persian 2
Snowshoe 2
Janese Bobtail 2
Siamese 1
Janese Bobtail 3
Russian Blue 2
Somali 1
Snowshoe 1
Tabby 3
Striped Tabby 2
Tabby 2
Striped Tabby 1
Sphynx 1
Sphynx 3
Maine Coon 3
Janese Bobtail 1
Russian Blue 1
Striped Tabby 3
Somali 2
Tabby 1
Persian 1