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