Panel 2: In HL2, a flying Scanner robot snaps your picture when you step off the train (and at plenty of other times).

Panel 6: A Strider is a huge, three-legged robot; only his foot is visible here (in combat, the Strider can impale people with it, which is cool). There is no Strider in the train station in the game, I spawned the ragdoll, which was tough to pose since it's so big.

Posing notes: In Panel 1, the cop on the right and the one pointing near the end of the trains are posed ragdolls, the other citizens are live spawns.