Passport control: for an inostranyets, it seems to take the clerks/officers or whatever approximately 1 minute to deal with each person - that's assuming there are no problems. It can be longer if there is an irregularity with the documents.
On a busy day, such as a Saturday in summer, they might (just might) have 5 officers working concurrently.
This results in horrendous queues in a hot, unpleasant environment. I waited 1.5 - 2 hours this Saturday.
I happen to know that this is not particularly unusual, it's happened to me before. The quickest I ever got through was in about 45 minutes (leaving is usually a bit quicker than coming in).
I've done a lot of travelling, and I don't think I ever encountered anything as bad as that. Maybe India, I don't really remember except the airport was damn hot there.

The main thing about Russian doors is just the sheer number of them. It's quite normal to have to go through 4 between the street and your apartment. That is really strange for an Englishman, who never has more than 2. 'Fort Knox' as we always used to say.