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)
All puzzles completed.
Complete a Speedrun in under 600 seconds. (start from options menu)
Complete 20 puzzles.
Complete Level 18 without cutting an arm.
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