Here is the full list of all 9 Akin achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Solve all time puzzles with a total of less than 15 minutes
Solve all puzzles on time mode
Solve 50 puzzles on time mode
Solve all puzzles on normal mode
Solve 25 puzzles on time mode
Solve 50 puzzles on normal mode
Solve 10 puzzles on time mode
Solve 25 puzzles on normal mode
Solve 10 puzzles on normal mode