Half Life 2: Episode One was developed by Valve and released in 2006, around one and a half year after previous game Half Life 2. It was Valves failed attempt to turn the Half Life franchise into an episodic format, as only another episode would follow before the series went into hiatus in 2007. Episode One is like its predecessor a classic first person shooter, the gameplay is pretty much unchanged, while the graphics have gotten a little upgrade. The story picks up mere seconds after the inconclusive end of the previous game. The player plays again as mute scientist Gordon Freeman.
The game starts out with the big explosion at the Citadel in City 17, the Vortigaunts intervene and rescue Alyx and Gordon Freeman, who then try to make it back into the Citadel to stop its core from exploding. This part of the game plays very similar to the ending of the previous one. Gordon's gravity gun gets super charged again and much time in the Citadel is spending shooting energy orbs into receptacles to activate bridges and other machinery. Once out of the Citadel both Alyx and Gordon have to make it through a bunch of dark underground passages. In these passages there is essentially no light and the only source of illumination is Gordon's flashlight, which happens to be constantly short on battery power. Once out of the darkness the rest of the games takes place overground in City 17 where ultimately the city is abandoned and the remaining humans are trying to leave the city by train.
The core gameplay is taken essentially unchanged from its predecessor and contains all the old issues. Running around in the world still feels overly smooth, like gliding on ice, not like a realistic walking human. The player character still has no 3D model and is just a floating camera, which especially in a scene right at the beginning where he is sitting in a car just looks a little ridiculous. This also makes some of the jumping parts of the game a little more annoying then they should be, as its hard to judge how close the player is to an edge when there is neither feed nor shadow to provide any reference. Interaction with NPC is again non-existent. Alyx follows the player around through essentially the whole game this time and while she can die, in theory, in practice she is almost invulnerable and provides plenty of supporting firepower. New weapon are not provided as far as I can tell and the environments all look pretty much exactly the same as in the previous games. Aside from the mentioned 'energy orb into receptacle' puzzle, the game also has a few physic based puzzles again that have the player place stuff on or under a seesaw to be able to reach the other end. None of those however feel interesting or clever.
In terms of controls the game supports gamepads more or less out of the box, the support, while playable, feels however rather rough. The few tutorial messages on the HUD still mention the keyboard keys, not the gamepad buttons. The zoom is done by clicking and holding the right stick, which is extremely uncomfortable and should have been a toggle instead (can be worked around by using XPadder). The weapon switching feels extremely bugged, it comes in three forms, a HUD-less quick switch, a pie menu and a menu at the top of the screen. Switching between the quick select and the menu is possible via the option menu, which kind of menu the player gets however seemed rather random, one is intended for the gamepad and one for the keyboard, but a few times when configuring things I ended up with the keyboard one on the gamepad. The game also had a huge issue where not all of the weapons would be selectable via the dpad menu, instead I only could select weapons from the first four groups, with the rocket launcher and grenade, even so collected, not available in the menu at all. After the game crash and I had to restart it, Steam started to download a patch, and after that the problem was gone and the rocket launcher would be displayed in the dpad menu. Not sure if the patch or restarting the game was the cure and neither am I sure what kind of patch Steam even downloaded, as the copy of the game itself was just freshly downloaded itself and I would hope Steam would download the latest one, not an old unpatched one, but anyway, after being first rather confused why the rocket launcher would just disappear I could finish th game.
Overall it is a tolerable game, but it feels incredible boring and uninspired. Essentially everything the player has to do in the game, he has already seen in Half Life 2. All the puzzles feel recycled, the weapon are recycled and the environments are all recycled as well. There is literally nothing of interest here that one hasn't already seen in Half Life 2. And the only new thing are the dark sections of the game, however those are also the most annoying due to the tiny cone of light and limited battery and don't contain anything interesting other then being extremely dark. In terms of story the game is also rather mediocre, as hardly anything of interest happens. It's essentially just an act of running from the Citadel to the train station to then escape with a train. The ending is also just as inconclusive as the previous game, fading to the credits after the Citadel explodes. Level design stays extremely linear, leaving even less freedom then in the previous game. Vehicle sections are absent and the game can be finished in around five hours. Also didn't like the characterization of Alyx much, as she ended up looked more like a Gordon Freedom groupie then a colleague or friend.
It's essentially more Half Life 2, but without having the bonus of being something new and so everything ends up feeling recycled and a little tedious.