This is a pretty simple game, so there aren't too many ways for it to be bugged. Lately, though, it's been pretty bad.
It interrupted one of my puzzles to ask me to review the game, which would be completely fine, if not for the fact that it erased my progress and I was nearly finished with that one, which was particularly challenging.
Additionally, the small model of the shape you have to make that appears above the grid has display issues. It will disappear entirely or overlap with the image of the last shape, which makes the puzzle virtually impossible for most people.