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