The columns create invisible walls (especially if there are two of them together). Sometimes the dead bodies create invisible walls above the body. When the third gate opened up, the game when freeze in certain areas and in certain positions. One cannot rotate all the way around after that without being frozen and one cannot walk to certain places.
Don't get me wrong, this is a good game. Just take a look at everyone else's comments. However, it is buggy and I hope that the bugs one day get swept out.