Hi Chatter, thanks for your wordy feedback and for the beta-testing!!
The trope is indeed a rather public one, especially since reincarnations already existed in Greek mythology (even with Orpheus going to hell to revive Eurydice). So yes, it was interesting to make a river, the flow which drives people to the underground in mythology, the place of death and rebirth here.
And that was exactly the setting: I didn't want to focus on the journey to bring Ambrose back to life, it would be the previous part of the tale. Instead, I chose to focus on the "solution" to refer the terminology I used for the "How to structure a fairy tale" OUAT post I made a while ago. We're at the moment where the tale should be solved, Ambrose should go back to life and live happily ever after with River... But alas, here, happily ever after is quantified, and the two lovers have to face their greatest enemy: time.
That's also why the endings, more or less happy, are overall all bittersweet: River's decision has consequences and in this situation, perfect happiness cannot be found. You highlighted it pretty well! Even in general, your analysis is ON POINT, per usual!
I'm also glad Ending 3 came as a surprise! I guess it's the one ending making the strongest statement about selfishness! I'm pretty happy with how this ending turned out, haha, although my favourite is indeed Ending 2, since it is the "empathetic" one, for a lack of better phrasing!
And of course, thank you for complimenting all the technical stuff: I'll admit I'm happy with how this game ended up looking!! I'm glad it was worth the wait because this game almost was my Waterloo fgfdfgfc