The button now flashes green as shown the screenshot. It starts off like that for some reason but I’ll leave it for now. I’ll have to think about how to use this animation for other cases where you have to press a certain button to progress the game like when you have to summon a creature as part of a card effect. I’m also thinking whether a black overlay should be added or not so players know what to concentrate on.
What’s next: looking into these issues and then back to testing