Hello! The smallest assets are 512x512 (Is that too big? Maybe I should make them smaller).
I made a little test for you at 640x360. You definitely lose some of the paper texture but you're bound to at a smaller resolution.
Thanks for your kind words 😊
Thank you for taking the time to make a full mockup, that was very nice of you! Out of curiosity, was there a specific base resolution you had in mind when making the initial assets? Even though my game's base resolution is 640x360 right now it's still a fairly early prototype and I think I could realistically change the base resolution without too much difficulty.