Here is the full list of all 36 Hot Tub Simulator achievements.
End 50 streamings
Pop 100 extra viewers bubbles
Do ASMR 10 times
Dance 10 times
Draw 10 times
End 10 streamings
Upgrade ASMR to max level
Reach streamer rank 1
Upgrade Dance to max level
Do Jumping Jacks 10 times
Upgrade Jumping Jacks to max level
Upgrade Draw to max level
Do squats 10 times
Upgrade Squats to max level
Get 1000 subs
Buy 6 zones
Reach 5000 viewers
Get 500 subs
Pop 10 extra viewers bubbles
Dance 1 time
Do ASMR 1 time
Get 100 subs
Buy 10 bikinis
Buy 5 bikinis
Buy 3 zones
Buy 1 zone
End 1 streaming
Reach 1000 viewers
Do Jumping Jacks 1 time
Draw 1 time
Buy 1 bikini
Reach 500 viewers
Pop 1 extra viewers bubble
Get 20 subs
Do squats 1 time
Reach 100 viewers