Here is the full list of all 8 Ragdoll Funhouse achievements.
Complete the 'Tutorial' Course Time Trial in the Tutorial level
Complete the 'Monkey Bars' Course Time Trial
Complete the 'Rollers' Course Time Trial
Complete the 'Side to Side' Course Time Trial
Complete the 'Climb' Course Time Trial
Complete the 'Crowded' Course Time Trial
Complete the 'Moving Walls' Course Time Trial
Complete the 'Slides & Zipline' Course Time Trial