GTA Liberty City Stories Easter Eggs

Moon Increases in Size
When it's night-time, take out your Sniper Rifle and look for the Moon in the sky. Zoom in and shoot the Moon. The Moon will increase in size the more you shoot it and then go back to it's original small state when you shot it enough times.

You aren't supposed to be here, pt III
In the back alley of the Libery Tree Bank in Staunton Island, climb over the wall and go to the far north west corner of the alley. There is now a sign that says,

"You just can't get enough of this alley, can you?" and a cartoon smile with arms on a plastered up poster.

GTA III has a sign that says "You aren't supposed to be here." and the PSP version of this game has a sign in the same place that says "Hello Again" with a smile.