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