Factual error: Why is there a stellar observatory in the middle of a very large city, most of the stars would be drowned out by the city lights to the point of the observatory being useless. Also, the dome is very high up on top of a "building". Such buildings need to flex a little bit in the wind to keep them from breaking, this would make it impossible for the telescope to focus on anything for a timed exposure of film to make those neat pictures of galaxies and such. (00:35:20)
Factual error: There are many instances in this movie where ice is doing things that ice doesn't do in the real world. Examples include Mr. Freeze freezing the pipes to make a hole in the wall, ice making things crumble all of a sudden, or something shattering easily just because a vehicle drives through something that is covered in ice.
Factual error: If everyone had been frozen for that length of time, their blood would crystallise, which would kill them. I imagine some of the buildings and anything made of glass might crack as well, but I don't really know about that.