Reversion - The Meeting has a total of 25 Steam achievements, 16 that are story related and earned as part of your natural progression and 9 which are missable, these are very clearly labelled in my guide below so make sure to familiarise yourself with them before commencing play.

It is possible to earn 100% achievements with just one playthrough, you will however have to save your game twice and load the game back up twice at different points to avoid having to complete multiple playthroughs to 100%.

Save point 1 = When you encounter the hungry soldier guarding the door to a house.
Save point 2 = When you discover the final door.

You will also have to ensure that you do not use the in game hint system (a button with a question mark on it in the top left of the screen) and you will need to complete the game in under 4 hours (it should take about an hour using this guide).

The achievement guide below is listed in the order in which I unlocked them. At the end of the achievement guide is a full video walkthrough earning all achievements.

Introduction
Start a new game

When you start a new game a conversation ensues between the protagonist and a lady called Victoria, after the conversation finishes a window opens up showing the game's controls and once this is closed the "Introduction" achievement pops.

See video walkthrough part 1 between the 0m00s and 1m36s marker.

Mystery man

After the initial conversation with Victoria speak with the man hiding behind the telephone booth (he is not always visible and pops his head out on the right hand side from time to time). During the conversation options, select "I think Victoria contacted you, to meet us here...", at the end of the conversation he will give you a Subway Map and this achievement will pop.

See video walkthrough part 1 between the 2m10s and 3m00s marker.

The Mechanic

After speaking with the man hiding behind the telephone booth, take a look at the Subway Map and then look at the front of the telephone booth and remove the Wires, then head off screen to the left, your GPS will open up, use it to fast travel to the Hospital.

Climb the rope to head inside the Hospital, head through the red door into the Hallway, then through the open door into the Warehouse, grab the Floor Drier and head back into the Hallway. Enter the Bathroom (the bottom right door) and pick up the Crowbar from the floor and the Jar from the counter, leave the Hospital and head back to the Obelisk (the starting location).

Head down into the Metro and examine the bin near the entrance to obtain a Screwdriver and head back upstairs to the Obelisk. Then use the Crowbar on the boot of the car (the back panel), then use the Lubricating Oil on the Battery and finally remove the Battery with the Screwdriver, once removed this achievement will pop.

See video walkthrough part 1 between the 3m10s and 6m35s marker.

Subway Erudite
You know all the stations by heart

***WARNING THIS ACHIEVEMENT IS MISSABLE***

Car Battery in hand, head back down to the Metro, stroll over to the far right and grab the Shovel head on the floor near the subway map. Go to the Metro line B (it's behind the riveted pillar with a frame leaning up against it, behind the red barriers), following the line B track to the right there are three stations, C.Pellegrini, Florida and Alem.

To earn this achievement you must examine the red name signs for each of these three stations along the line B track.

See video walkthrough part 1 between the 7m08s and 9m16s marker.

Subway Meroder
Take a stroll through the subway

***WARNING THIS ACHIEVEMENT IS MISSABLE***

To earn this achievement, when you are at Alem station on line B, simply walk to the right and you will end up back at C.Pellegrini station and the achievement will pop.

See video walkthrough part 1 between the 9m16s and 9m26s marker.

Secret Door

When walking the Metro line B you will notice a number of levers along side the tracks in the following locations...

Lever 1 = Between C.Pellegrini and Florida stations.
Lever 2 = At Florida station.
Lever 3 = Between Florida and Alem stations.
Lever 4 = At Alem stations.

These levers have to be pulled in a certain order to open a secret door and to unlock this achievement. The order is 2 > 1 > 4 > 3.

See video walkthrough part 1 between the 7m11s and 10m36s marker.

Bullseye
Resolve the subway puzzle without retrying

***WARNING THIS ACHIEVEMENT IS MISSABLE***

This achievement relates to the Secret Door achievement, pull the four levers in the correct order first time and this achievement is yours.

Lever 1 = Between C.Pellegrini and Florida stations.
Lever 2 = At Florida station.
Lever 3 = Between Florida and Alem stations.
Lever 4 = At Alem stations.

The order is 2 > 1 > 4 > 3.

See video walkthrough part 1 between the 7m11s and 10m36s marker.

The Electrician

After opening up the secret door, walk on through to encounter... another door. First, grab the Hammer and Nails on a crate to the right of the secret room door and then speak with the occupant through the intercom and tell them "I'm here on behalf of Victoria" they will then try to open the door and the electrics blow.

After your conversation with Victoria on the GPS, use your Screwdriver to remove the cover from the electric panel, remove the burnt battery and install the car Battery and Cables you salvaged earlier.

Then go back to the intercom and tell the occupant "Try to open the door now" and sure enough your fix did the trick, the door opens and this achievement pops.

See video walkthrough part 1 between the 10m42s and 13m18s marker.

Broken Shovel
You can't dig with a broken shovel

***WARNING THIS ACHIEVEMENT IS MISSABLE***

Once the door to the secret room is open, head on in, take an Alfajar from the candy box and then speak with Pablo (it's the guy that was hiding behind the telephone booth at the start of the game) selecting "Could you help me? I need to find this person..." from the conversation options.

Conversation over leave the Metro and at the Obelisk walk off screen to the left and head to the new location on your GPS, the Waste Land. At the new location open your inventory and separate the Stick form the Floor Frier, then attach the Stick to the Shovel Head and proceed to try and dig up one of the graves without properly securing the Shovel Head and this achievement will pop.

See video walkthrough part 2 between the 0m00s and 3m08s marker.

The Carpenter

Having broken the Shovel by trying to dig a grave without properly securing the Shovel Head open up your inventory once again. This time attach the Stick to the Shovel Head and then secure the Shovel Head with the Nails and Hammer that you obtained from outside Pablo's Hideout, with the Shovel properly repaired this achievement is yours.

See video walkthrough part 2 between the 3m10s and 3m30s marker.

Thief

***WARNING THIS ACHIEVEMENT IS MISSABLE***

Repaired Shovel in hand dig up two of the graves that stand before you, one is empty, the second will contain a military uniform and a note bearing an address. Head off screen to the right and use your GPS to fast travel to the "House" (the address found on the note in the grave).

Here you are greeted with a half demolished house and a female soldier sitting on a crate and a Flashlight on the ground behind the girl, simply try to pick the flashlight up and the "Thief" achievement is yours.

See video walkthrough part 2 between the 3m30s and 5m16s marker.

The Informant

After trying to steal the female soldiers Flashlight at the House, speak with her and select the "What's Happening?" speech option followed by "He may not be dead, he may be hiding or somethink like that" (it should say "something").

It turns out the female soldier is pining for her boyfriend whom she seems to think is dead, your earilier tomb raiding however, implies he is perhaps not, Maria (the female soldier), hands you a Photo and asks you to let her know if you find her boyfriend.

Photo in hand head off screen to the left and use your GPS to fast travel to the Hospital and once again climb up the rope to gain entry. Inside the Hospital ward, there are three beds, the closest to the window appears to be occupied, examine the bed to discover the occupant is Maria's boyfriend.

Armed with this information, head back to the House and speak with Maria telling her "I found him!", conversation over Maria leaves to find her boyfriend and this achievement is yours.

See video walkthrough part 2 between the 5m16s and 7m35s marker.

Tomb Raider

Once Maria has left to find her boyfriend, grab the Flashlight off the floor that she left behind and then head off screen to the left using your GPS to fast travel to the Waste Land. Then use your shovel once last time to dig up the final third grave and this achievement is yours.

See video walkthrough part 2 between the 7m35s and 8m24s marker.

Sleeping Candy

***WARNING THIS ACHIEVEMENT IS MISSABLE***

After digging up the final grave, you discover an ID card with an address on it, head off screen to the left and use your GPS to fast travel the address found on the ID card (also listed as "House", it's the one just above the Hospital on the map).

You arrive at the address to find a hulking soldier standing guard over the entrance, the first thing you must do here is SAVE YOUR GAME.

FINAL WARNING, make sure you save before carrying on, ok, don't say I didn't warn you.

Next, open up your inventory and use the Syringe with the Sedative Bottle, then use the Syringe with the Alfajar and offer it to the soldier guarding the door... sadly this has no effect on the guard but your actions do net you the "Sleeping Candy" achievement.

See video walkthrough part 2 between the 8m24s and 9m46s marker.

Exploding Candy

With your failed attempt to sedate the guard out of the way, load up your save game that you made when you first encounter the guard. This time use the Syringe with the Laxative Bottle, then use the Syringe with the Alfajar and give the alfajar to the guard. This time around not only do you earn an achievement, you also get some results leading to the guard leaving his post.

See video walkthrough part 2 between the 10m02s and 10m50s marker.

Remembering

With the guard now otherwise disposed, open your inventory and use your Crowbar (obtained from the Hospital bathroom) to remove the planks barring the door and then head on inside the house.

First, grab the UV Light Bulb from the lamp sat on top of a bookshelf near the entrance, then head over to the couch and interact with the tear in the back cover and a Key will fall on the floor. Collect the Key and then walk in front of the couch to the TV stand and use the Key that you just collected with the drawer on the left.

Inside the drawer you will find a sheet of paper with a number on it, with this in hand, move over to the three paintings on the right wall and interact with the one on the far left, behind it you will find a safe and the number you found on the paper in the drawer is the combination (5829).

Open up the safe and sift through the documents within to earn this achievement.

See video walkthrough part 2 between the 11m00s and 14m40s marker.

Flier Shoos

Once you have finished rifling through the safe, exit the house, walk off screen to the left and use your GPS to fast travel to the Obelisk, head down into the Metro and follow line B to Pablo's Hideout.

When you enter the Hideout you receive a garbled message from Victoria through your GPS which ends abruptly, conversation over, replace the bulb in the blue lamp with the UV Bulb in your inventory (obtained from the light with the house that had a guard on the front door) and the light will uncover a clue scrawled on the wall and the "Flier Shoos" achievement will be yours.

See video walkthrough part 3 between the 0m00s and 1m37s marker.

The Student
Visiting the house of knowledge

Armed with the information left for you by Pablo, exit the Metro back to the Obelisk and walk off screen to the left and fast travel to the Engineering Faculty on your GPS and as soon as you enter the Engineering Faculty building the achievement is yours.

See video walkthrough part 3 between the 1m50s and 2m23s marker.

Usher

Once inside the Engineering Faculty building, you discover the lifts are out of order and the stairs up are blocked, so head downstairs, the lights are off so you turn on your Flashlight (stolen from Maria earlier) and the achievement is yours.

See video walkthrough part 3 between the 2m23s and 2m53s marker.

Lowering Water
Finding the right combination

Now in the Engineering Faculty basement with Flashlight in hand, shine the light to the right to locate and flick the light switch. Open up your inventory and use the Serum Holder on the ceiling fan to dislodge the Elevator Key and grab it once it drops to the floor.

Then open the shutter, activating the switch on the left hand side and walk through to grab the Gloves resting on the railings. Pass back through the shutter and close the shutter with the switch and as you do, you will remove the Shutter Key and then head back upstairs.

Use the Elevator Key on the elevator doors to open them and then use the Gloves to climb down the elevator shaft and you will find yourself on the opposite side of the shutter doors that you encountered when you went down the stairs.

Use the Shutter Key with the switch on the right of the shutters, the shutters will open and a panel will also unlock to the left of the shutter doors. Head over to the newly unlocked panel and you will be greeted with 16 buttons, each bearing a letter from the Greek alphabet.

So whats the code....
1. The Janitor said just before you climbed down the elevator shaft "pi (π) comes first".
2. Omega (Ω) is painted on the wall above the stairwell inside the Engineering Faculty building.
3. Rho (ρ) is on a piece of paper on the wall to the right of the leftmost elevator.
4. Lambda (λ) is painted on the wall outside the Engineering Faculty building.

Enter the code π, Ω, ρ, λ, the water will drain in the tunnels below and the "Lowering Water" achievement will be yours.

See video walkthrough part 3 between the 2m54s and 6m02s marker.

The final door

With the water now lowered head down the ladder and through the tunnel on your left to be greeted with a locked gate, examine the padlock and then head back upstairs (note you can't go back up the elevator so go back through the tunnel, up the ladder, through the shutter to the workshop then down towards the bottom of the screen to return back upstairs).

Then examine the cardboard box to the right of the left elevator to find a pair of Lock Cutters, once again use the Gloves to head down the elevator shaft, go down the ladder and through the tunnel to arrive back at the locked gate.

Use the Lock Cutters to remove the padlock and head through the gate, then follow the red cable through the tunnel on the left, again follow the red cable, this time through the right tunnel to encounter "the final door" and this achievement will pop.

NOTE, it is very important to SAVE YOUR GAME BEFORE YOU OPEN THIS DOOR !!!

See video walkthrough part 3 between the 6m02s and 8m20s marker.

Winner
Finish the game

FINAL WARNING, make sure to save your game before opening "the final door".

Once you go beyond the final door, a cut scene plays out followed by the credits and then a final short cut scene eluding to the third chapter of the game, once this final cut scene has played the "Winner" achievement is yours.

See video walkthrough part 3 between the 8m20s and 11m01s marker.

Riddle Guy
Finish the game without using the hint system

Reversion - The Meeting has a hint system to helkp you if you get stuck, much like a hidden object game, this hint system is accessed by clicking on the round button bearing a question mark (?) in the top left of the screen. If you want to earn this achievement DO NOT CLICK ON THIS BUTTON and as long as you do not this achievement will pop at the same time as the "Winner" achievement.

Marathon Runner
Finish the game in less than 4 hours

To earn this achievement simply complete the game in under 4 hours and it will pop at the same time as the "Winner" achievement (following this guide you should be able to complete it in about an hour).

Double Winner
Finish the game for a second time

Right, remember I told you to save before going through "the final door" well with your first playthrough complete you should be back at the main menu, so load up that save file now.

Standing back outside "the final door" once again, simply go through it and complete the ending of the game, watch the credits and then the final cut scene and this achievement is yours.

See video walkthrough part 3 between the 11m03s and 13m37s marker.

For anyone with problems viewing the embedded videos in this guide (such as those in China having to use a VPN to watch videos on YouTube) here's a link to the playlist...
https://www.youtube.com/playlist?list=PLgrKGjfHCc0j4dzzTHmyyYj2cyqHsSRQD

I hope you found this guide of help, all comments, suggestions and criticism (constructive) is gratefully received.

An A to Z list of my Steam achievement guides and walkthroughs can be found @ https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1502405720
If you would like to get a notification in your activity feed when I post a new guide, just click the "follow anrkyuk" button on my profile guide list...
https://steamhost.cn/steamcommunity_com/id/anrkyuk/myworkshopfiles/?section=guides