Here is the full list of all 7 Boris the Sloth achievements.
Die 100 times.
Dash killed 3 or more enemies at one time.
Find the secret level.
Take revenge on the evil mandrake that kidnapped Euka.
Defeat the bear that is guarding Euka.
While in the spirit realm, hop out of and back into the anti-gravity portal without touching the ground (or vice versa).
Collect all of the sleeping frogs that are used for the time warp ability.