When you start out in the train, keep walking forward until you see Alyx with the gravity gun. If she say's 'Back up.' You should back up. After the doors gone, walk to Alyx, and wait until she's done talking. She will give you the gravity gun, the same thing with episode 1, you should walk to the little pond and find out the solution. Listen to Alyx, and she should be talking about the core, then when the core sends a wave, you should walk through the little entrance that one of the rocks opened during that wave. Head in and get rid of the wood the is blocking the cart, then don't stand in front of it, go behind it, and it should crash into a wall. Keep going and you'll see zombies. Kill them and then get rid of the wood that is blocking you. You should look in a room, and you should see an elevator with saws, then you will see your crowbar stunning the saws, use your gravity gun to pick it up, and your elevator should fall. Keep going and you may find many weapons if you turn --> and head in. Use your crowbar to smash the boxes for items. You should get the shotgun, the pistol (I don't remember if you even get the pistol) and the grenade. After that, walk out of the room and you should see an acid antlion worker. If you kill it, you will get the achievement - Acid Reflex. More coming soon. So, how did you like the FAQ? If I got anything wrong, please email me at [email protected] and I shall make changes.