There is a secret trophy room in Sonic Generations.
Hold down Select or Back button while inside the Collection Room.
Once inside the trophy room, trophies are unlocked by inputting 6-digit codes.
How can players discover such codes by their own?
I'm not interested in a list of the codes. I know I can search the web and find such list, but doing so spoils all the fun. What I want to know is how can I discover such codes by myself. Does the game give some hints about the codes? Did SEGA release hints somewhere outside the game?