1. This walkthrough is played on the normal difficulty setting on the Xbox 360. Before game play begins, a CGI animation dramatizes key moments from Half Life 2: Episode One.
2. The beginning point-of-view can be a bit disorienting. Look down to find yourself in a demolished train car. Work your way to the far end of the train.
3. Wade through the water to the next car ahead.
4. Look up to see other rail cars on a train bridge. The game has picked up after the train sequence of Episode One.
5. Alyx finds you and sets you free with the Gravity Gun, which she promptly hands over. Proceed up the hill over her shoulder.
6. The Gravity Gun's right trigger will blast open this door.
7. Follow as Alyx is astonished to see the Citadel in ruins. A portal storm flashes through.
8. Turn around to witness the destruction of the railway bridge. Spectacular.
9. Enter this tunnel, revealed by the portal storm.
10. Use your Gravity Gun to clear away a wooden plank, then drop down here.
11. Clear away more planks then toss these flammable canisters at the zombies to help Alyx defeat the crowd. (Is it a crowd of zombies? Herd? School? Murder?)
12. Find health packs in the supply crate before entering the communications center ahead.
13. Help Alyx get the equipment running by plugging the third plug into the red socket. She comically assumes she made the fix.
14. Watch as Alyx reaches White Forest on the screen, and learn that the data she is carrying is the key to defeating the Combine.
15. Exit out the door opposite after finding this gnome under the nearby bed. (An homage to the Traveling Gnome Prank.) You will earn the "Little Rocket Man" achievement if you launch him into space later in the game. That means a lot of gnome babysitting, but I'll tell you when you need to bring him along. You can leave him here for now if you don't mind a bit of backtracking later on.
16. Continue through here, being sure to open the health packs in this supply crate. Follow the stairs to the right, careful to avoid the toxic head crab.
17. Remove the boards preventing this rail sledge from sliding downhill. It will crash through the boards below, allowing you to exit.
18. Climb this hill on the right then catch a glimpse of something odd on the roof to the left. Drop down on the other side of the fence.
19. Alyx wants you to find a way to open the gate on the left. Climb this ladder on the right.
20. Follow the roof to this opening. Drop through after clearing the metal sheeting with your Gravity Gun.
21. Use this switch to raise the gate.
22. Remove the plank to open the trap and exit. A supply crate with med packs is below.
23. Alyx is attacked by something called a Hunter. It looks grave, but a friendly Vortiguant will try to revive her.
24. You can backtrack to the gnome now if you like (jumping from the train to the hillside climbed earlier.) The way ahead is to clear these boards passed the newly-opened gate.
25. Put the gnome is this elevator and jump in. Grab the crowbar to get it moving.
26. Smash the boards blocking your path to exit the lift. Note the suit armor in the locker ahead.
27. Continue through this door.
28. Carrying the gnome is a bit troublesome during this next part. Set him down on the lift then turn the crank. The lift will rise, but will drop as soon as you let go, or until you reach the top. You want to end up where that antlion carcass is, but the completionists will want to grab the health and energy one level up. I made three passes up, one to get the health, one to get the energy, then a third to quickly grab the gnome and jump across.
29. Clear a table away and find a pistol before dropping through this hole. Don't let go of the gnome -- the ground here is unstable and you could lose him for good.
30. Find suit energy on a nearby shelf then drop through another hole in the ground. Beware a toxic head crab below.
31. Bust through more boards then drop into this water hole.
32. Swim up (Press A) then climb onto this ledge to enter the cave.
33. Your Gravity Gun's right trigger will clear away these glow worm webs.
34. There's only one path through the tunnel, but you won't be coming back through here so bring the gnome. Note that live glow worm grubs grant one point of health when touched.
35. Blast another web then drop through here. Quickly ready your pistol.
36. An acid antlion is down here. Be careful not to get too close when he explodes. You can just barely see shotgun ammo ahead/right.
37. Follow the tracks to this room on the left where you'll find a shotgun to go along with the ammo. More supplies can be found if you duck under the boards at the end of the tunnel.
38. Back in the shotgun room, find suit energy in the locker ahead then smash these boards to drop through with your gnome.
39. Clear away pallets and these boards. You're now behind the fence across from the shotgun room.
40. More acid-spitters. Ascend the ramp on the right.
41. Blast through another web and defeat another spitter before dropping off this ledge with your gnome. Note the supplies ahead/left.
42. Take your gnome for a swim -- the path ahead is through this underwater tunnel.
43. Antlions become prey to barnacles in this next chamber.
44. An acid spitter leads you to his pals. Lure them into the tunnel on the left for an easy double-barrel shotgun kill.
45. After smashing another web, grab your gnome before advancing down this ledge to load the next level.