Here is the full list of all 23 Clockwork achievements.
Control Milli
Die during the Act 1 Boss Fight
Idle for 5 Minutes
Solve a Puzzle with a Shamblebot
Solve a Puzzle using a Time Remnant
Fix a Leg
Finish the First Level
Play the Game
Play the Game for Two Hours
Finish Act 01
Finish Act 02
Finish Act 03
Finish the Game in One Session
Beat the First Boss without Dying
Beat the Final Boss without Dying
Die during the Act 3 Boss Fight
Kill a Shambler
Solve a Puzzle with a Box
Solve a Puzzle with a Sentry
Die 5 times in one level
Place a Portal
Use a Portal
Fix the Generator