Some achievements are only obtainable in the dev build. If you're not getting an achievement, try deleting gamestate.txt from the game's folder and restarting the game.

However, some achievements might briefly stop working in either the "owf_staging_prep" or the "owf_development_build" due to updates potentially breaking an achievements trigger logic, so it's always good to ask. There's also a very early access build locked behind a donation for those so inclined.

Start The Game. - Load the main menu.

game SUCKS - Quit the game.

sv_cheats 1 - Load into any map and type "sv_cheats 1" in the console.

Play Hunt Down the Freeman at 3AM????? - Set your time to anything between 3 and 4 am, load into a map and wait for the HL2 Citadel screams to play.

No Refund - Play the game on one save file for 2 hours or more.

And it crashed... - Crash the game and open it again.

100% - Get every other achievement.

Pvt. Dirtbag - Die in the tutorial. Fastest way is to blow yourself up in the grenade tutorial. Map: a0c0p0

Fresh Out of Basic - Finish the tutorial Map: a0c0p0

CONE - Pick up the cone inside the Black Mesa supply closet near where you get the MP5. Map: a0c0p1

F*cked face. - Finish the chapter. Map: a0c0p1

There was a knife? - Finish the chapter without picking up the knife. Map: a0c0p1

IHATEGLASS - Break all 146 glass panels in the map. In the owf_staging_prep build you only need to break all the glass in the lobby which is 60. Map: a1c2p3

Authorized Personnel Only! - Just before you meet Adam, turn right and drop down the elevator shaft. Map: a1c2p3

M203 Mastery - At the start of the chapter, after picking up the M16 you must land 3 direct hits (easy difficulty) with the grenade launcher on the gunship. Map: a1c3p1

M203 Mastery (owf_staging_prep) - Once you make it outside into the canals, after going through the tunnel the gunship will spawn and you must land 2 direct hits on the gunship (any difficulty) using the M16 grenade launcher attachment. Map: a1c3p2_canals_2

DEVY - At the start of the claymore section, look into the barricaded room on the left side of the hallway to see a cuboid with dev textures. Map: a1c3p4

Death by Claymore - Run into a Claymore in the train station. Map: a1c3p4

You Should Really Stop That - Run into Larry triggering one of Larry's voice lines 30 times. Pressing your "interact" key (by default E) will not work. Map: a1c3p4

In God We Trust - Listen to President Gnomestar's surrender speech. Map: a1c3p5

This is the part where you meet Joe. - Meet Joe. Map: a1c4p4

No Weapons (only in owf_staging_prep) - Pull the three levers down at the end of the Joe segment without using any weapons. Map: a1c5p2_factory

The Seven Hour Chore - Finish Act 1. Map: a1c5p4

Give a Little Bit (only in owf_staging_prep) - After the fight on top of the Combine gate bridge thing, climb on top of the hill to your right near the barricades and the shipping container with hunters to find a piano. Walk up to it to trigger the achievement. Map: a2c1p1_newalaska

Karen - Finish Act 2. Map a2c2p2

You Monster! - Kill all your child soldiers by dropping props on their heads. There should be 22 around the ship before the crowbar cutscene and 15 after. Bring the bench from the canteen with you so you can reach the ones past the invisible wall. In the owf_staging_prep build you only need to kill 1, not all of them. Map a3c1p1

The Wrong Way - During the map where you have to jump onto the train, go backwards. This will trigger a voice line and give you the achievement. Map: a3c1p2

Get Bullied - Finish the escape sequence in the third map and get captured by a CP. Map: a3c2p3

Can't Really Say I Like Him... - After the cutscene with Boris, interact with the Dr. Breen statue, then get on top of it. Next, parkour up the back wall and crouch jump on the statue until it breaks. Map: a3c2p4

Just To Be Sure Freeman Isn't There - Kill every rebel at Black Mesa East, including the two behind the turret. Map: a3c3p1

Down to Business - Pick up the double barrel shotgun at the start of the second map. Map: a3c3p2

Another Blow to the Face - Get killed by the staircase that drops down from the attic when you pull on it. Map: a3c3p2

You Actually Did It... (only in owf_staging_prep) - Kill Freeman while he's running away, it's at the same point that Mitchell yells out at Freeman, he's unkillable at every other point. Map: a3c3p2_ravenholm

Sneaky (only in owf_staging_prep) - Sneak through the antlion guard room in the cave without stepping on any grubs. Map: a3c4p1_cave

Betrayal - Hold out until Nick arrives and get the good ending. Map: a3c8p2

This is where you get on. - Die during the shootout and get the bad ending. Map: a3c8p2

Refund! - Finish the whole game (good ending) under 2 hours in a single playthrough (not related to your overall play time), starting from PROLOGUE (a hidden timer is triggered). Pro tip: Run from fights where possible. Map: a3c8p2

Work in Progress (only in owf_staging_prep) - Carry the traffic cone from the janitor closet in the Black Mesa map all the way to the end of the game. Boxes have been added to the back of all vehicles for easier transport and the cone will appear on the ground near the player on any maps that don't transition smoothly into one another. You also need to holster your weapons before climbing ladders with the cone. Map: a3c7p2_outpost