There is a weird bug on your "What do you want to learn about first?" question.
I am able to select both "Cheeseburger" and "Greek Salad" but not "Greek Salad" and "Spaghetti & Meatballs". If I tap "Greek Salad" after first tapping "Spaghetti & Meatballs" then it deselects the "Spaghetti & Meatballs" and selects "Greek Salad" (even with only 1 item selected).
I am able to select both "Cheeseburger" and "Greek Salad" but not "Greek Salad" and "Spaghetti & Meatballs". If I tap "Greek Salad" after first tapping "Spaghetti & Meatballs" then it deselects the "Spaghetti & Meatballs" and selects "Greek Salad" (even with only 1 item selected).
Anyway, cool concept.