Sure there aren’t that many cards but those cards are so well balanced. Every single card has its uses so you’re constantly presented with interesting decisions. It feels like almost every other roguelike has dead time where you’re just going through the motions whereas in slay the spire you’re making decisions from floor 1.
IIRC it is actually a different physics engine than BotW. BotW couldn’t handle all the physics interactions in TotK. That’s what’s so impressive about the game. Physics-based games are rare, especially for AAA-developers, because it’s just a lot of work. In TotK everything just works as you’d expect. You’re just looking at it from a gameplay perspective while ignoring the technical achievements.