You're right, the one card at the beginning is confusing; I plan on showing more at the onset to counter that.
I was hoping users would click the "show more cards" button when they got to the waiting screen, not actually wait 10 seconds. I should probably add some help text to encourage clicking this button.
The reason I'm experimenting with multiple choice over just asking "Did you get it right or wrong" is to make for a more casual learning experience. After a few days a card turns into typed answer so the user can prove to themselves that they still know it. I am considering adding a traditional flip and self score mode to accommodate users who want that.
My plan is to make a native app with Notifications; the SMS thing is just a temporary way to get the deck onto the phone since there's no login system yet.
If you have time, I'd love to pick your brain as to how you learn. If you do, shoot me an email: firstname.lastname@example.org . Thanks again!