I highly highly highly recommend two things to you if you haven’t played this game. 1) Play it. 2) Play it as absolutely blind as humanely possible.

One of my all-time favorite gaming experiences, and all the more precious because you can never have the experience again without suffering severe memory loss. The fun and the journey is in learning and understanding the world, the history, the science, and the mechanics that lead you to finding the ultimate ending. And oh what an ending it is (although there are a few alternates)!

Trust me, just pick it up and play without knowing anything at all about it. Don’t watch videos, don’t look up wikis, don’t read articles and don’t read forums. This game is best enjoyed without even the smallest spoiler. All of the information is in the game that you need and it’s all very very well thought out and executed. You’ll explore and find secrets that lead to more secrets. You’ll sometimes find yourself struggling to solve a problem, to put some pieces together, and then something will click into place and you’ll suddenly understand so much. It’s a great feeling. That’s what this game is about.

If you do need to get help, only look in fan forums or subreddits. People there are fans and understand the value of discovery in this game, so they will only give you some hints to point you in the right direction rather than outright answers, as it should be.

I had done everything in the game and had trouble with one little thing that i wasn’t piecing together to complete it, so i had to look up a hint for that, and everyone on the forums were really careful to only give as much information as you need, which i appreciate.

Details

Getting inside the ash twin project. I had even done all the quantum moon stuff - i wish that would have been integral to complete it or at least have given me bigger hints for getting inside

I really love the DLC as well, it’s more linear and thus more straightforward but it does a really good job at guiding you such that each discovery leads to the next one, and the tricks you learn to progress are really fun and creative.

Keeping things very vague, I was in the same position as you and “figured out the puzzle”, tried 3 times with no success (idk if something glitched?) and so I figured I was wrong. Spent another 5 hours looking around for another way with no success and had to look it up. It’s the only blemish on what was otherwise one of the best games I’ve played in at least a decade.