Wait -- I Think I Dropped My Wallet Back There Achievement

Details on how to get the I Think I Dropped My Wallet Back There achievement, no specific tips, just the way to get it without losing time wondering what to do.

⚠️ Important note

It seems that this achievement has been broken for some time on the current (oct. 2023) version of the game. If you still wanna go for it, you need to downgrade your game version to an older, working one.
Some guides and information are available in the comments below. Thanks to Brandonius for sharing the tips.

Preliminaries

First, you need to finish the game. After that, when you restart the game, you will spawn in the room between the second water hub and the space levels. This is where we start.

The journey begins... again

After you have finished and restarted the game, take the big door at the top of the room that leads to the second water hub. You don't need to do the Space part again.

Play the three levels in this part: Swamp #2, Wetlands, Winter. The order doesn't matter. When you enter them, the elevator will take you at the end of the level, you just need to get back to the other elevator.

Then, go to the first water hub, and play Midnight, Morning and Swamp #1 as well (no matter the order).

Finally, go back to the intro level, and play it to the first screen.

You did it! Congrats!

Notes

• Swamp #2 and Midnight are really easy to do backwards because all the wormkeys have been collected so you just need to take the portal to get to the first elevator.
  
• Wetlands and Swamp #1 are quite easy too, you don't need to solve the puzzle on Wetlands again, and there is no specific challenge in playing Swamp #1 backwards.
  
• Winter and Morning can be tricky sometimes, but everything has been well thought, and you don't need amazing new techniques to go through them.
  
• You don't really need to do first the three levels of the second hub, then the three levels of the first hub. It's just the obvious way to do it :) The intro level must be done last, though.

Thanks for reading!

Now go work on your Minimalist and Speedrun achievements!

[Frey]

Thanks, that explains why some people were unsuccessful following the guide's instructions.
For people coming here, here is a step by step guide on how to download an older version of a game:
https://www.reddit.com/r/Steam/comments/611h5e/guide_how_to_download_older_versions_of_a_game_on/
You obviously don't need to do steps 1 to 4, just use the IDs given by Brandonius on the comment below.
I recommend disabling automatic updates for the game before performing it.
Happy platforming!

[Brandonius]

This achievement is currently broken but I was able to unlock it by downgrading to the 2014 version of the game. You'll have to look up how to do it yourself (it's not too difficult) but to save some time, the console command is "download_depot 295750 295751 8612489685407121568" for Windows and "download_depot 295750 295753 1636934609297691354" for Mac.

[Frey]

Very strage... I'll be interested to know if your second attempt works.
If you ever find what's missing in this guide that can explain these missed attempts I'd be glad to add it.

[Ewen]

Same here, no luck. Don't know what I missed to get it. First attempt though. I might just reset and start over, don't know yet.

[Claytonic]

It's not working for me either. I went back through the 6 areas and then back ro the very beginning and nothing happened.

[Frey]

Ok, it loks very much like what you should be doing...
Maybe try:
- do space again
- save and quit after the end
- reload
- do the 6 main areas and the intro
And hopefully it works.

But I don't have better ideas...

[2Sleepee]

I have done the main 6 hub levels and then the first area. Going so far as to do all the levels in reverse order in the sequence that I did them when playing normally. The only two things I can think of are- do space aswell. Or explore every room of Midnight and Swamp 2

[Frey]

It's been a while, so it's hard to say. Are you talking about going back to the Space area? You should not do that. You should focus on doing the 6 main levels in the two hubs, and then the intro level.
If that doesn't help, could you post a screenshot or a small video to show what you are trying to do?

[2Sleepee]

are you not able to go through the first terminal in order to get past that room? What am I doing wrong? I've attempted this 3 times now