Here is the full list of all 12 Doc Clock: The Toasted Sandwich of Time achievements.
Complete every level without using the time slider.
Collect 75 robot heads.
Pick up twelve toasted sandwiches.
Sit in front of a TV for five minutes.
The gnome must be cast back into the fiery chasm from whence it came.
Perform a 540 degree flip in a vehicle.
Sound the bell ten times within ten seconds.
Propel your vehicle 150 meters into the air, using any means possible.
Collect 20 robot heads.
Fall into a pit of lava 3 times
Destroy a robot using a robot head.
Destroy five robots in two seconds.