Visible checkbox - Checkbox of some kind should be visible at all times to the left of the task. Swiping right to show the check box(circle) is not efficient.

Hi Steve, we hide the circle because we want to keep the interface clean since the mobile interface is already smaller than the web browsers. FYI, a quick tip, if you would like to complete multiple tasks at once, instead of swiping right on each task, you could swipe left from the edge of the phone, for the checkboxes to show up, select the tasks then tap on the circle to complete. Hope this helps.