Well people you have the game. what hidden easter eggs and secrets have you found?
I for one stumbled onto the 'heart of liberty city' which is located inside the statue of liberty on happiness island. you have to steal a helicopter and try to land on the top most platform (not a easy thing to do) once youve accomplished that look for a door that has the plaqs with "no secrets here" written on them. go through the door and up the ladder. there you will see a completly functional giant heart. beating. it's a bit creepy but it's the heart of the city.
so like i said. thats what ive found. share yours.