Here is the full list of all 50 Sylvio achievements.
Game finished with all piano sheets complete.
Looks like an exhibition of cave paintings.
Found all shreds of piano sheet five.
All notes and recordings found in the surroundings of the zoo.
Found all shreds of piano sheet one.
Found all shreds of piano sheet four.
Found all hidden messages
Communicated with guard at the zoo entrance.
Notes from the static : All found
Found all shreds of piano sheet two.
Found all shreds of piano sheet three.
Found all of Bobby's reels.
All notes and recordings found in the surroundings of the hotel.
Retrieved the hotel key from corpse hanging from giant balloon.
Communicated with Roger's lover in the hotel bathroom.
Found 100 hidden messages
Found arcade game no. 4
Shot the crow by the hotel rides.
All notes and recordings found in the main park of Saginaw.
Communicated with Robin in various places of Saginaw main park.
Blinked a combination, and the pump started.
Blinked a hidden combination on the signal lamp.
All notes and recordings found in the surroundings of the funfair.
Communicated with Susie on the funfair.
All notes and recordings found in the surroundings of the big house.
Notes from the static : 60 found
Found 60 hidden messages
Communicated with Kristoph in the trailer by the big house.
All notes and recordings found in the surroundings of the ice cream hut.
Communicated with unknown by the ice cream hut.
Notes from the static : 40 found
Found 25 hidden messages
Found arcade game no. 3
Found arcade game no. 2
Notes from the static : 20 found
All notes and recordings found in the cellar.
Notes from the static : 10 found
Communicated with Daniel in the cellar.
Found 10 hidden messages
Played the piano in the auditorium.
Notes from the static : 1 found
Found one hidden message
Found arcade game no. 1
Used the entertainment system in the restaurant.