13 Sentinels is super impressive. It's a narrative masterpiece.
Unicorn Overlord became one of my favourite games of all time as soon as I played it on release. The artwork is phenomenal and the gameplay deep and rewarding. It's only drawback for me being that it was too easy even on the hardest setting and the narrative was rather lackluster.
In the last few weeks I've just gotten into 13 Sentinels and the narrative is blowing me away! Apparently Kamitani spent 5 years planning out the parallel stories into massive flowcharts to ensure the story can be enjoyed in pretty much any order you choose. And the hard sci fi setting, sense of mystery and suspense, as well as the character development and dialogue are all exceptional. In contrast to Unicorn Overlord the gameplay is more basic and shallow, it's kinda like if you only got the real-time map and movement and Valor skills of UO, but it's still pretty fun.
I know this game has been out for a while now, and I'm probably preaching to the choir, but you gotta go check out this game!
It's so worth getting through the prologue chapters because after that it opens up and the story might be one of the best that's ever been realised in a video game. Certainly in terms of sci fi.