the player can cheat under certain conditions; if there is only one tile left on a row, the player can flag it and if it is a mine, the row will clear. if not, the player can unflag it and click it. not sure how big a deal this is really.
In IE8, blank tiles do not cascade after clicking, nor do mine counts update properly. I think this is a problem with callbacks on jquery animations. I don't plan to support IE8 but this could be indicative of problems in other browsers.