Dark Souls seems to carry a lot of themes from Heidegger's Contributions, his lectures on Nietzsche and Nietzsche's Will to Power, especially the ideas of a eternal recurrence, fading flames and oblivion, although because both game and writer here are pretty difficult, that would be a tougher sell. I might expand on these ideas in a video at some point, if I find the time.
If you want some philosophical games, I'd recommend the YouTube channel Errant Signal, who does more in-depth analysis' at games, especially more thought-provoking indie ones that might escape your radar otherwise.