there are tons of Columbine student projects on YouTube (some even from this year) that are filmed inside the school. The biggest change is that the library is gone and in its place is a high ceiling with art on it. The stair case has a glass window above it and there is large text on the landing that is a tribute to the class of 2004. There is a brand new library built at the back of the school where the garbage cage use to be.
The back entrance that Eric and Dylan entered has been remolded to be in line with the cafeteria wall, instead of being far back like it use to be. The stair case outside has been totally remodeled with the old dirty hill replaced with rock cylinders that lead up to a patio. The sign out the front is now digital, and there is a art across all the walls of the hall way and a revolutionary soldier statue. The carpeted floors have been removed so now the floor in the halls is a shiny surface. Where the old library door was is now a window that over looks the cafeteria.