Here is the full list of all 41 Hot Lava achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Complete one sticker set.
Pick up a pair of scissors and run with it.
Complete a community map course.
Complete all Tiny Toy trials.
Complete all courses and trials in Master Class.
Complete all Pogo trials.
Complete all courses.
Unlock all courses in Master Class.
Complete all pursuit courses.
Complete all courses and trials in Basement.
Unlock all courses in Basement.
Unlock a follower.
Unlock all courses in School.
Complete all courses and trials in Wholesale.
Unlock all courses in Wholesale.
Complete all courses and trials in School.
Find the hidden fort in Wholesale.
Complete all courses and trials in Playground.
Unlock all courses in Playground.
Pick up a knapsack and run with it.
Get a basketball into the hoop in Playground.
Use a water fountain.
Jump 5000 Times.
Complete a course with Buddy.
Lose Buddy to the lava.
Complete your first "pursuit" course.
Complete all courses and trials in Tutorial.
Unlock all courses in Tutorial.
Complete a Tiny Toy trial.
Complete a Pogo trial.
Jump 1000 Times.
Complete all challenges for a single course.
Die by Collision.
Build up boost to 5 m/s.
Complete a course with no deaths.
Perform a "late" jump right after leaving a ledge 77 times.
Complete the first course in Tutorial.
Unlock your first character.
Jump 100 times.
Tweak something in the Options menu.
Complete the Intro.