I think adding an option to adjust the speed is a great idea. I’ll definitely look into that for a future update. As for the deck selection, I love the idea of incorporating more unique and zany options, like decks with only odd cards or missing cards—I'll keep that in mind as I continue to improve the game. Looking back I think it would have been nicer to have the computer have just black suits and the player only red suits, or completely shuffled like I had, and to read out the suit as well as the value.
Thanks again for your feedback, and I appreciate your support!