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