Here is the full list of all 9 Handshakes achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Complete a Speedrun. (start from options menu)
Complete a Speedrun in under 600 seconds. (start from options menu)
Complete Level 18 without cutting an arm.
All puzzles completed.
Complete 20 puzzles.
Complete Level 11 by cutting an arm and shaking a Hand simultaniously.
Complete Level 10 without cutting an arm.
Complete 10 puzzles.
Shake a Hand