Ruguelite progress manifests in higher depths (difficulty levels), unlocking more cards, characters, character passive abilities and shrines (difficulty modifiers). There is a lot of game-mode variety - you can build your starting deck and possible card pool, or you can draft the starting deck and let all unlocked cards be in the possible card pool. There is also a rush mode if you prefer shorter runs

PS. The only reason I've had to "tinker" with the game is because I have an optimus system and my integrated GPU driver is not new enough to work with Proton. The Nvidia driver is.