Remembering what was when over 45 episodes spread over years can be rough. Hopefully this will help you out.
'''Note: Astute gamers may infer spoilers from what is below. Everything is unmarked for ease of reading. You have been warned!'''
[[folder: Hazard Course ]]
* Episode 0: Freeman goes through the training course. Stops at the "Jump to Target" part as he doesn't want to be injured.
[[folder: Black Mesa Inbound ]]
* Episode 1: Freeman [[BlackMesaCommute rides the Tram to work]].
[[folder: Anomalous Materials ]]
* Episode 2: Freeman finds his way down to work.
* Episode 3: Freeman arrives at the test chamber and starts the "green apocalypse".
[[folder: Unforseen Consequences ]]
* Episode 4: Makes his way out of test chamber.
* Episode 5: Freeman continues his way out of test chamber (to the lobby) and finds a pistol.
* Episode 6: Jumps in a sewer, takes a lift that takes a long-ass time to go down, and gets stuck at a walkway.
* Episode 7: Freeman plays Extreme Hopscotch.
[[folder: Office Complex ]]
* Episode 8: Encounters bugs, electricity, maintenance shafts and a machine gun turret.
* Episode 9: "'''Okay children, class is in session! Everybody take your seats! ''I said everybody take your seats!!'' Dammit Billy, that means you too!'''"
* Episode 10: Goes through a freezer section before finding a vending machine to get Doritos.
* Episode 10.5: Freeman messes up a jump, falls to his death.
[[folder: "We've Got Hostiles" ]]
* Episode 11: Freeman hops over lasers and finds an [=MP5=].
* Episode 12: The "rescue team" arrives.
* Episode 13: Freeman finally gets to the surface.
[[folder: Blast Pit ]]
* Episode 14: Finds a shotgun, heads downward and takes a tram to a pool of "radioactive...crap".
* Episode 15: Arrives at the rocket testing engine.
* Episode 16: Freeman wanders around silos and spots a large fan.
* Episode 17: Returns to the rocket propulsion test chamber.
* Episode 18: Restores all power to the rocket engine.
* Episode 19: Finally fires rocket engine.
* Episode 20: Jumps down a smoking hole where the alien used to be.
[[folder: Power Up ]]
* Episode 21: Encounters the large blue alien (Gargantua).
* Episode 22: Turns on the power generator for the tram.
* Episode 23: Freeman makes it back to track control, only to realize power is still "off".
* Episode 24: Defeats the Gargantua and gets the tram working.
[[folder: On a Rail ]]
* Episode 25: Goes around in circles on the tram, encounters a machine gun turret and ends up at a broken elevator.
* Episode 26: Takes the tram back to the area with the crane and heads upwards (with the tram).
* Episode 27: Speaks like a pirate the entire episode.
* Episode 28: Loses his tram (thanks to Rocky the Rocket Ranger) and is stopped by explosives.
* Episode 29: Back on the surface.
* Episode 30: Launches satellite.
[[folder: Apprehension ]]
* Episode 31: Decides to head back down after being shot, takes another tram, and finds a big pool.
* Episode 32: Encounters shark-thing (Ichthyosaur).
* Episode 33: Bypasses the giant pistons and discovers he's being tracked.
* Episode 34: Ninjas, Gordon captured.
[[folder: Residue Processing ]]
* Episode 35: Wakes up in trash compactor, can't remember who what he did yesterday.
* Episode 36: Wanders around the room full of canisters filled with the same radioactive crap, and gets lost.
* Episode 37: Finally remembers what happened.
* Episode 38: Rides conveyors.
[[folder: Questionable Ethics ]]
* Episode 39: Passes through Bio Labs, stops in lobby.
* Episode 40: Enters area with four lasers that converge into one.
* Episode 41: Escapes Bio Labs, reaches Dam.
[[folder: Surface Tension ]]
* Episode 42: "'''That ''Damn'' Dam! Damn.'''"
* Episode 43: Runs around in circles while being harassed by helicopter.
* Episode 44: Cliff-climbing, a rickety bridge, and a rocket launcher. Finally takes down the helicopter from the last episode.
* Episode 45: Freeman is [[MajorGeneralSong the very model of a modern major general.]]
* Episode 46: Dodges falling debris, avoids landmines, theorizes about alien gravity and the benefits of an extra finger, meets the sniper from Episode 31 again.
* Episode 47: Stumbles through the trip-wire maze, shoots an alien weapon dead, laments his inability to hotwire a military vehicle, and gets pinned down by a "[[TanksButNoTanks tank]]".
* Episode 48: After blowing up the "tank", Freeman plans to become the Film/LordOfWar, plays air traffic controller with a rocket launcher, and teaches a guard about the importance of knocking before opening.
* Episode 49: Freeman displays his skill in "shotgun chess" amid [[MeleeATrois alien vs soldier]] combat, considers if he has murdered enough people to alter the course of the timeline, and gets told to put a well placed satchel charge in his pipe and smoke it.
* Episode 50: Gordon almost shotguns another security guard, is disappointed in his lack of stamina and self-preservation instinct, and finally uses him as a decoy to escape another Gargantua. He also needs an airstrike map of the whole world.
[[folder: "Forget About Freeman!" ]]
* Episode 51: Freeman laments his OneManArmy status while navigating through Snark mines, only find himself at a dead end.
* Episode 52: Gordon ponders if he's taking the longest possible route through the facility while hopping in and out of water, avoiding mines, sharks, and automated guns while he and the military keep each other's life interesting. Also, more rockets, another dead tank, and a suspiciously quiet elevator.
* Episode 53: Freeman hopscotches around radiation, finds a tank, and ponders the rarity of stupid aliens in media and the possibility that humanity is just better at invading places, stopping at a hallway full of blood.
[[folder: Lambda Core ]]
* Episode 54: Freeman vs. Ninjas 2: ElectricBoogaloo.
* Episode 55: As Gordon heads into the reactor core, he worries about guards that may have gone rogue.
* Episode 56: Freeman contemplates honor in battle as he prevents a nuclear meltdown.
* Episode 57: Freeman gets high off morphine as he discovers "portable stars".
[[folder: Half-Life: Uplink ]]
* Episode 58: Freeman, still high, takes a detour into Half-Life: Uplink, where he thinks about the cover-up of the cover-up, hears his returning ghost, and realigns a radio antenna. The episode ends when he decides he can't fit through a small gap.