I liked the problem and the build up of this episode - the problem with stargate. I have so many times watched some things going trough there and wondered - mm.. what happens if they are stucked there. In this episode, it comes out. All the time counting thing and that everything there seems to be going on the same time scale than episode on real time.
The only thing that looked weird for me - all the shocking thing. I would be quite sure that poor Sheppard would have get little brain damage as they did not managed to get him up very quick and they spent much time on the jumper before they get him to the stargate.
But it was really good episode. Lot of nerve-wracking moments.