Half-Life 2 Walkthrough -> Nova Prospekt
Use the gravity gun to slash the machine guns you encounter in the prison, or grab them and toss them aside. We move through the abandoned rooms until we reach an empty hall, bathed in moonlight. We descend into it.
An antlion awaits us there. Killing it isn't too difficult. Run away from it and make active use of red barrels and other weapons. After that, we clear the debris from the blocked double doors:
Accompanied by our larval friends, we run out into a corridor blocked by a gate with a red light glowing above it. It's locked, so we head into the perpendicular corridor, where there's a guard booth, the entrance to which is blocked by an energy screen, and a dead Vortigaunt sits in a chair:
We break the fan
We unplug the cable, enter the guard booth, and press the switch. A door to the stairwell opens next to the booth. We climb up to the second floor and press the button by the window in the next guard room. Doors open in the first corridor.
After passing through, we see the corridor blocked by a wide energy shield. We climb into the hole in the right wall. We block the fan we encounter along the way with boards and other debris lying nearby.
Having disabled this gate, we continue on, through numerous prison rooms, until we find ourselves in a security room with a broken window.
A pressurized nuclear physicist
Down below, there's another room where an antlion awaits us, from which we can escape through a door blocked with debris:
Next, there'll be a scramble between two black walls that will begin to close in when we reach the middle. Don't panic (but if you hesitate for more than a minute, you'll be trapped by the fence). There's a gap where the fire is burning, easily accessible by placing a box against the wall. End of Chapter Nine. Next, we'll encounter the Vortex.
Source: halflifecity.narod.ru