Here is the full list of all 100 Mosaique Neko Waifus 2 achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
SOLVE ALL CHEN AND SUYIN PUZZLE
ALL GIRLS JUMP OUT OF THEIR CLOTHES
SOLVE FIRST CHEN AND SUYIN PUZZLE
FINISH SARA AND SAYOURI EXTRA PUZZLE
FINISH NIKO EXTRA PUZZLE
SOLVE ALL SARA AND SAYOURI PUZZLES
SOLVE ALL SAYOURI PUZZLES
SOLVE ALL NIKO PUZZLES
SOLVE ALL SARA PUZZLES
SOLVE ALL CHEN PUZZLES
VIEW 100 PHOTOS
SOLVE 40 PUZZLES
COLLECT 40 ITEMS
SOLVE 35 PUZZLES
COLLECT 35 ITEMS
SOLVE 1000 BLOCKS
SOLVE 30 PUZZLES
COLLECT 30 ITEMS
SOLVE 900 BLOCKS
COLLECT 25 ITEMS
SOLVE 25 PUZZLES
FIRE "EARTHQUAKE" 10 TIMES
VIEW 2 PHOTOS
COLLECT 20 ITEMS
SOLVE 20 PUZZLES
SOLVE 800 BLOCKS
GAIN 30000 EXPERIENCE
SOLVE 700 BLOCKS
UNLOCKED "SECRET PRESENT" IN SKI
LEVEL UP TO LEVEL 30
SOLVE 600 BLOCKS
CLICK A PIECE WITH "SECRET PRESENT" 5 TIMES
LEVEL UP TO LEVEL 25
UNLOCKED "FLASH BOMB" IN SKILL TREE
SOLVE FIRST SARA AND SAYOURI PUZZLE
GATHER 7 UNSPENT ABILITY POINTS
SOLVE 500 BLOCKS
SOLVE 20 PIECES USING "FLIP ALMOST SOLVED"
"LOVE SPARKLE" FIRED 50 TIMES
LEVELED 20 ABILITIES IN TOTAL
FIRE "CHOCOLATE AIRSTRIKE" 30 TIMES
LEVEL UP TO LEVEL 20
SOLVE 400 BLOCKS
SOLVE 15 PUZZLES
CLICK A PIECE WITH "SECRET PRESENT"
COLLECT 15 ITEMS
CLICK THE PUZZLE PIECES 1000 TIMES
LEVELED 15 ABILITIES IN TOTAL
SOLVE 300 BLOCKS
GAIN 10000 EXPERIENCE
CLICK THE PUZZLE PIECES 900 TIMES
LEVEL UP TO LEVEL 15
CLICK THE PUZZLE PIECES 800 TIMES
CLICK THE PUZZLE PIECES 700 TIMES
"FLARE" FIRED 15 TIMES
SOLVE 200 BLOCKS
UNLOCKED "EARTHQUAKE" IN SKILL TREE
UNLOCKED "LOVE SPARKLE" IN SKILL TREE
SOLVE 10 PUZZLES
SOLVE FIRST CHEN PUZZLE
CLICK THE PUZZLE PIECES 600 TIMES
COLLECT 10 ITEMS
GATHER 5 UNSPENT ABILITY POINTS
LEVELED 10 ABILITIES IN TOTAL
GAIN 5000 EXPERIENCE
CLICK THE PUZZLE PIECES 500 TIMES
LEVEL UP TO LEVEL 10
CLICK THE PUZZLE PIECES 400 TIMES
"LOVE SPARKLE" FIRED 10 TIMES
SOLVE 100 BLOCKS
CLICK THE PUZZLE PIECES 300 TIMES
UNLOCKED "PEEK" IN SKILL TREE
CLICK THE PUZZLE PIECES 200 TIMES
SOLVE FIRST SAYOURI PUZZLE
SOLVE 5 PUZZLES
SOLVE FIRST NIKO PUZZLE
SOLVE 50 BLOCKS
CLICK THE PUZZLE PIECES 100 TIMES
UNLOCKED "FLIP ALMOST SOLVED" IN SKILL TREE
COLLECT 4 ITEMS
COLLECT 5 ITEMS
LEVELED 5 ABILITIES IN TOTAL
CLICK THE PUZZLE PIECES 50 TIMES
COLLECT 3 ITEMS
LEVEL UP TO LEVEL 5
VIEW 1 PHOTO
UNLOCKED "CHOCOLATE AIRSTRIKE" IN SKILL TREE
UNLOCKED "FLARE" IN SKILL TREE
COLLECT 2 ITEMS
SOLVE 2 PUZZLES
SOLVE 10 BLOCKS
SOLVE 1 PUZZLE
CLICK THE PUZZLE PIECES 10 TIMES
COLLECT 1 ITEM
SOLVE FIRST PUZZLE WITH SARA
GATHER 2 UNSPENT ABILITY POINTS
SOLVE 1 BLOCK
LEVEL UP TO LEVEL 2
CLICK THE PUZZLE PIECES FOR THE FIRST TIME
HELLO THERE!