Hey there, thanks for playing!! I'm glad you liked it 😊 I love all your suggestions! Some of them will be a part of the full game, like there being more decks and cards, and music throughout! Having an achievements / challenges list is definitely something I also want to include, as well as a global currency for cosmetics 😊
The sacrificial altar should always return a card, but in the demo requires a random number between 1-3 of cards to be sacrificed before you get one back!