Clicking on the Undo button during animation should be simply ignored, instead of waiting for the animation to finish and then quickly do an undo. I think ignoring this would provide a smoother game experience. If I click on it now, then the Undo is so fast that it is hard to follow what happens on the screen. And I think the Undo will be used rarely, so lots of undo clicks will be accidental, too.
Clicking on the Undo button during animation should be simply ignored, instead of waiting for the animation to finish and then quickly do an undo. I think ignoring this would provide a smoother game experience. If I click on it now, then the Undo is so fast that it is hard to follow what happens on the screen. And I think the Undo will be used rarely, so lots of undo clicks will be accidental, too.