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