Library of Ruina is, similarly to Slay the Spire, a card battler. However, instead of controlling one unit, you usually control a small squad with individually customizable builds. LoR is a story focussed game based on the events of Lobotomy Corp. Prior knowledge is however not necessary to play LoR. I highly recommend this game and it's one where I would advise to go in without spoilers.
Why I recommend this:
-Great story and characters
-Scratches the itch for a challenging card battler
-Large build variety
-Memorable boss fights
-Each story mission/chapter is replayable
What might be a deterrence:
-The difficulty spikes can be frustrating
-Builds will need upgrades throughout the game to stay relevant.
-Story and character development starts of slow
-Can be slightly grindy as upgrades are somewhat randomized on mission rewards
To get all of the endings, it took me a bit over 100 hours.