Early game spoilers ahead so please proceed on your own terms!
I recently finished Undertale by playing through the neutral route and later the pacifist route. The entire experience was awe-inducing to say the least and I finally understood why the game became so popular.
The moment that made me shed my tears was during the fight with Toriel. As I had taken up the pacifist route back then, I kept sparing her for all my turns and attempted to dodge her attacks. Eventually I was overwhelmed by her fireballs and brought down to 2 HP before I could get to skip the battle portion of the encounter.
When I proceeded to spare her as before and witnessed her taking her eyes off me and disarming her menacing expression, I started to experience a weird emotion. I braced my heart, barely hanging on to life, for another brutal round of attacks, only to watch all the fire projectiles begin to evade me, which only amplified this unknown emotion further.
That's when I realised what I was experiencing: sympathy for the protagonist and Toriel's unbounded and unspoken compassion towards each other. By "sparing" her for yet another round, the protagonist was declaring that they didn't wish to fight her, despite being brought to the verge of death by her attacks and knowing that they may not survive the next one. Meanwhile Toriel, possessing the ability to decimate the human along with sufficient motive to do so, ultimately couldn't find it in her heart as a mother to end their life as she went on to quietly express sorrow and guilt in her face afterwards while continuing to "fight". This scene of self-sacrifice and remorse was complimented by Toriel's fight theme song, resembling the tone of the tragedy of fighting a battle neither one of whom wanted to fight, ending up in a stalemate.
I don't know if there was something inherently unique about this moment, for some reason I immediately started shedding tears uncontrollably. It was as if this level of compassion and sympathy was untold of that overflowed my brain, ultimately making me feel sadness and happiness simultaneously. I ended up like this whenever I saw the screenshot of the fight or watched the recording of someone else's afterwards and eventually this moment became special to me. Even as I was writing this post, I happened to cry 3-4 times.
I don't know if someone else has had this experience before, either in this game or some other media, but if anyone does, I would really love to hear about it. Either way I feel like dumping this up here as an appreciation for the game dev for the wonderous journey the game made me go through.
As someone who also has played Outer Wilds (up to first half of the DLC), even I was left saddened when I learned the fate of the Escape Pod 3 crew. Back then I was in rush to find their spaceship so I didn't pay that much attention to their scene, but looking back at it now hurts me way more. At least I feel good about the Nomai in the solar system having accomplished something to get themselves as well as future civilisations closer to the secret behind the Eye of the Universe that they'd take pride in before meeting their eventual demise. In fact I believe they would've accounted for the possibility of their species getting wiped out before the completion of their goal one way or another. That or they just do universally good documentation.
Oh shit. I never realised it even though I remember the corpse near the warp station. I guess this answers my lingering doubt about what happened to the Nomai supposedly inside the impenetrable core of the Ash Twin Project during the Interloper incident.
Personally I didn't get the ending. I was constantly switching between the two hypotheses about the meaning of the ending ie.
Both hypotheses were dissatisfactory, so I just formed my own headcanon that the story ended on the protagonist's arrival at the Eye. Still, the part with the instruments of all the explorers combining into an orchestral harmony was mesmerising, especially with the piano tune from the Quasi-Nomai.
If you want to read my (and some others) interpretation of the ending feel free to read the spoiler. If you do not want to alter your headcanon (which I can totally understand, personal experiences are a powerful thing and as the name says: personal), just ignore it.
spoiler1
The ending is the end of that universe. The eye is in a quantum superposition and what we see is similar to 2001: A Space Odyssey: an interpretation to make sense for our hatchlings brain so to say. You, the hatchling enter the eye and thereby a conscious observer collapses the wave function that was the eye.spoiler2
What you see first when you enter the eye is probably meant to show the quantum world behind reality, so to say, with the purple tornados (purple was the color of the quantum moon and the eye after all). Then you get to the forest where all the different lights symbolise the universe and its galaxies and stars. And they all go out one by one, meaning you see the heat death of the universe happening in fast forward. Then you are running alone through a dark forest and then even the forest vanishes, which symbolises the universe itself getting broken down to the bare functions where everything, even distance stops existing till only you in the eye exist, which is why you find yourself at the end of that sequence, because everything besides yourself has stopped existing.spoiler3
Then you get teleported to the second clearing, which is happening.... outside of time/inside your mind/outside of existence? I think trying to nail that down is a futile task, it is all meant to be symbolical in my eyes. We are talking about metaphysical stuff here after all. It is where the new universe will be born, where you collect the other travellers. These are all being born from how the hatchling imagined them, but the lessons they symbolise stay with the hatchling nonetheless: everything ends, and that is fine; we have to overcome our fears in order to advance and be able to accomplish anything; etc.By collecting them, you are gathering the instruments that will create the very basic fabric of the next universe. Depending on what you experienced as hatchling, that will determine how the next universe will work, physics and all.
If you managed to reach Solanum, there will be alien life in the end slide, because you experienced alien life yourself and therefore in the next universe, it will be there as well. If you managed to find the Stranger, the end slide will show inside out planets, because that artificial world changed your idea about how planets have to work and thereby that directly influences how the next universe is going to work. If you managed to finish the DLC, that will be incorporated as well. I will not spoil it, but I highly recommend finishing the DLC, the ending of it was very emotional for me.
spoiler4
So, fitting to what we experienced all during the game: the eye is the quantum superposition of the next universe, so all possible futures and by the hatchling entering it, the new universe is chosen from all possible versions (including how physic laws are going to work). Then you see it being born and die in that moment, knowing that the universe and life in it carries on, a new cycle beginning.spoiler5
So to speak: the egg of the new universe is broken and its birth happen because you were there. What would have happened if no observer were there is unclear, maybe the new universe would still have been born but life would have needed to develop by random chance, as opposed to being included into the very fabric of the universe from the start. In the worst interpretation, no conscious observer means the egg never breaks and no new universe is being born, instead being trapped in the superposition for all eternity, as no new consciousness can develop to reach it after the end of the universe.spoiler5 gives an interesting interpretation that does make sense within the context of the ending. Instead of the player's efforts being for naught, they help in the birth of a new universe not possible before. Unlike the initially perceived ending, it finally gives the story closure in my mind.