Here is the full list of all 13 Lexica achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Complete all medium Puzzles
Complete 192 Puzzles
Complete 15 Puzzle Packs
Complete all easy Puzzles
Complete 96 Puzzles
Complete 5 Puzzle Packs
Complete 48 Puzzles
Complete 24 Puzzles
Complete 12 Puzzles
Complete a Puzzle Pack
Complete your first Puzzle
Complete all 288 Puzzles
Complete all hard Puzzles