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
Do Jumping Jacks 10 times
End 10 streamings
Reach streamer rank 1
Upgrade ASMR to max level
Do squats 10 times
Upgrade Dance to max level
Reach 5000 viewers
Upgrade Jumping Jacks to max level
Upgrade Draw to max level
Get 1000 subs
Buy 10 bikinis
Buy 6 zones
Get 500 subs
Upgrade Squats to max level
Pop 10 extra viewers bubbles
Dance 1 time
Buy 3 zones
Do ASMR 1 time
Reach 1000 viewers
Get 100 subs
Do Jumping Jacks 1 time
Buy 1 zone
Buy 5 bikinis
Buy 1 bikini
Draw 1 time
End 1 streaming
Reach 500 viewers
Get 20 subs
Do squats 1 time
Pop 1 extra viewers bubble
Reach 100 viewers