There will be spoilers for the game and the DLC in my text and the comments
If you don’t want to be spoiled, play the game first, it’s a really really nice game that’s best when discovered
My favourite moment for the game (as for most players), was when I fetched the Warp Core and had to go to the Nomai Ship. The music made my heart beat so much, and the trip seemed so friggin long.
But my best discovery within the game is understanding how simply turning off the flashlight would be enough to make the quantum objects move. It was so satisfying discovering it for the first time.
I think the best moment for me was probably
spoiler for the base game
The sun station. After way too much time figuring out how to get there, the music, and the story stuff to read there? Such a good moment.
spoiler
It’s a shocking revelation when you discover the sun station doesn’t even do anything, when up to that point you might think to yourself that it’s the sun station that causes the supernova.