Jail Break addon - Half-Life 2

My first real single player map, I've been working on Gmod maps for awhile now, but I've never tried taking the time to make a single player game. The map doesn't actually have an end, but when you go in the really dark tunnel, that's supposed to be the end.

Story:
You play a rebel leader who's been imprisoned in one of the Combine's prisons high in the mountains. You wake up to your wall being broken open by the other imprisoned rebels, they've escaped and are breaking you out to lead them! You plan to exit through the back of the prison and sneak back to City 17 using the old train tunnels.

There is a hidden gravity gun and Easter egg, if you can use your mind to find it. The Gman is watching!