After finishing Half-Life Alyx i have decided to create a guide for missable achievements. This guide will not cover achievements you you can get by just playing the story.
There will be very minor spoilers for gameplay content especially in the chapter exclusive achievements, there will be no/minimal spoilers regarding the story itself.
These achievements will be obtainable in every chapter as long the requirements are met, these are not locked to certain chapters however the objects/enemies might be.
Use the gravity gloves to loot an item off a living Combine Soldier
Loot a corpse
Use the gravity gloves to intercept an incoming enemy grenade in mid-flight
Kill a Combine Heavy while their shield is up
I recommend to damage the heavy first with a grenade then shoot at his chest. Once his shield is up throw another grenade and take cover. Do not keep looking at him after throwing the grenade or he will flash you and his shield might dissappear before your grenade explodes. You can also damage him with bullets if you don’t have 2 grenades, however you need to do enough damage or he might not die.
Pick up and smash 50 glass bottles.
Kill a grunt by shooting their gas tank.
For me, shooting at the gas tank itself did not work, however shooting at the valve of their gas tanks does. I recommend to use a sight for this.
Use the multitool to hack a tripmine.
Smash and Grab
Break open a suppy crate with your hands.
These are the missable achievements in Chapter 1
Eye of the Geiger
When Russel is done explaining the plan and sits down, grab the Geiger counter across him and use it on his face.
Feed the snark
In the early beginning you will find a room with a camera and an insect in a jar on the table. Grab the can next to it that says ‘NOT COFFEE’ and feed the snark by shaking it.
Gnome Vault of My Own
Grab the garden gnome after getting the gun from Russel and carry it all the way to the end of Chapter 10. The gnome is hidden on a couch behind a pillow left underneath Russel’s window.
Catch Russell’s ammo magazine before it hits the ground.
After getting your first gun, Russel will throw a mag which you need to catch mid-air.
On a Roll
Interact with the playground somehow
When you arrive at the playground, grab the small red bucket near the slide and roll it off the slide.
Represent yourself with specific prop on Russel’s Map
After Russels asks you to grab something to represent them, use the small baseball figure near you.
Missable achievement in Chapter 2.
Test your grip on a headcrab heart.
When you meet the Vortigaunt, there is a dead headcrab with a heart in it and nearby a bowl headcrab hearts. Grab a heart and squeeze it.
These are the missable achievements in Chapter 7.
Kill the annoying headcrab before it breaks everything
After the elevator you come into a hallway with a headcrab crossing a plank infront of you. kill the headcrab before it knocks anything off.
At the end of Chapter 7, lure Jeff into the trash compactor and activate it.
Hold Your Liquor
Catch a bottle falling out of a cupboard before it breaks and alerts Jeff.
In the alcohol storage room, there is a cabinet where if you open it, a bottle starts to roll off. Grab the bottle before it hits the ground.
Stay near Jeff for 10 seconds (but not too close)
Escape the distillery without killing Jeff.
Go through Chapter 7, at the end you can lure Jeff into a container and lock him in, do not activate the trash compacter.
Bring Russel a bottle of vodka.
Go through Chapter 7 and reach the start of Chapter 8 with a bottle of vodka, you can store it in your wristwatch.
Gnome Vault of My Own
Remember the garden gnome from Chapter 1? Your journey with him ends here.
Important: While using the elevator, drop the gnome on the big box. If you hold it in your hands the gnome will disappear.