Here is the full list of all 36 One True Cuddle achievements.
Clear tutorial stage.
Clear 1st area.
Get all stars in 1st area.
Clear 2nd area.
Get all stars in 2nd area.
Clear 3rd area.
Get all stars in 3rd area.
Clear 4th area and obtain the Shadow gene.
Get all stars in 4th area.
Clear 5th area.
Get all stars in 5th area.
Clear 6th area.
Get all stars in 6th area.
Clear 7th area.
Get all stars in 7th area.
Clear 8th area.
Get all stars in 8th area.
Complete all notes by talking to everyone.
Stomp 3 times in a row without touching ground.
Stomp 5 times in a row without touching ground. But you might be able to do more.
Stomp 10 times in a row without touching ground. You are the best!
Take no damage from Kitty Soldiers (In NORMAL difficulty)
Take no damage from Bomber Dog (In NORMAL difficulty)
Take no damage from Mother Slime (In NORMAL difficulty)
Take no damage from Shadow Hugger (In NORMAL difficulty)
Take no damage from Underlings United (In NORMAL difficulty)
Take no damage from Frog Captain (In NORMAL difficulty)
Take no damage from Silent Bunny (In NORMAL difficulty)
Take no damage from Detro (In NORMAL difficulty)
Take no damage from Kitty Soldiers EX (In NORMAL difficulty)
Take no damage from Humans (In NORMAL difficulty)
Take no damage from Detro C (In NORMAL difficulty)
Take no damage from Neo Detro (In NORMAL difficulty)
Clear normal ending sequence
Clear true ending sequence
Collect all 160 stars.