So I know the time it takes to play Half-Life 2 (15 hours), but it seems like the entirety of Half-Life 2 + Episode 1 and Episode 2 is only a week long. Gordon arrives, meets up with his old Black Mesa pals (although they only open the door for you in HL1 but who else were they going to pick?), makes more noise than a Skull & Bones invitation, go through the coast, go to jail, protest, tell Dr. Breen that he sucks and then witness him get so affected by it that he destroys himself, then retreat and blast a rocket into a portal. Sure, that makes it seem small, but that's what it feels like. So, in the lore, how long does the events of HL2 + Episode 1 and Episode 2 take?
About two weeks, though only a few days from Gordon's perspective.
We can tell by the lighting in the outdoors levels that two days pass before Gordon and Alyx escape Nova Prospekt. The game begins during daylight and then it's night by the time Gordon is going through Ravenholm. It's light again for the car journey along the coast then getting dark as he's assaulting Nova Prospekt.
The "slow teleport" from Nova Prospekt to Kleiner's lab takes over a week according to Kleiner. So more than 7 days but less than 14 - probably closer to 7 or he would've rounded up.
The assault on the Citadel takes place during daylight again, although the lighting makes it seem like dawn or dusk. This stays consistent until the explosion at the top of the Citadel, so this section is only a few hours at most (which would roughly match the gameplay time).
After that, there's another time gap which an old post from Marc Laidlaw describes as "a few days" (see the section "Time between HL2 and Episode 1"). It's not exactly specified in-game but it was enough time for Alyx to regroup with her father and then leave to search for Gordon, so a few days seems reasonable.
The events of Episode 1 and Episode 2 are all in daylight, getting towards dusk by the rocket launch at the end of Episode 2. They seem to take place in pretty close to real time, which (according to howlongtobeat.com) is about 9 hours.
Choosing some plausible numbers, we've got:
- City 17 to Nova Prospekt - 2 days
- Slow teleport back to City 17 - 7-10 days
- Assault on the Citadel - 3 hours
- G-man and Vortigaunt-induced time gap - 2-4 days
- City 17 to the rocket launch site - 9 hours
Which is just under 12 days at the low end and nearly 17 at the high end. Either way, Gordon experiences nearly 3 days of constant, terrifying warfare without food, sleep, or a bathroom break. That MIT education really pays for itself.