Here is the full list of all 20 Mr. Sweet achievements.
You unlocked level 14
You unlocked level 13
You unlocked level 12
You unlocked level 11
You unlocked level 10
You discovered a new universe!
You unlocked level 9
You unlocked level 8
You unlocked level 7
You unlocked level 6
Buy more characters
You unlocked level 5
Collect 10,000 sweetcoins
Distance = 5000
You unlocked level 4
Buy more music
You unlocked level 3
Distance = 1000
You unlocked level 2
Distance = 500