Here is the full list of all 20 Saturnalia achievements.
Flash the Creature 5 times
Team up with another character 3 times to reach a destination
Replenish your stamina 3 times while the Creature is chasing you
Use 100 matches
Run out of stamina 5 times
Complete Claudia's Mission
Complete Sergio's Mission
Complete Anita's Mission
Rescue a captured character 6 times
Complete Paul's Mission
Distract the Creature 5 times using the firecrackers
Get captured while using a phone
Light up all the bonfires in Gravoi
Collect 3 tips from the Mouth of Truth
Complete Tecla's Act
Light all the votive candles in the church
Find all the tools and consumables
Read at least 90 clues
Use a phone 5 times to gather your companions
Turn on all the lights inside the Mines