From the trailers I thought it would be pretty much puerile, BBC Three-style sex jokes, and for about 75% of the time it was. The joke of an old woman saying "f**k" and talking about sex got old very quickly. I was hoping it would run for about 5mins then end, but it seemed to lag through the whole episode.
Fourth wall jokes seem to be quite key to the show, and while some people see it as clever, personally I see it as quite desperate. As for the pub scene with the bag, my guess is that it was intended. Fair enough it can give a nice connection to the actors and the audience/viewers, but too many of them can be tired.
There didn't really seem to be much of a plot. Whenever the main story (of Dermot's break up) was brought up, it was quickly lost again. Even in the key scene (the home therapy), they were intent on having as little about Dermot and Maria as possible, before distracting to a nearly completely unrelated back-story.
I agree with some people about the energy of Mrs Brown giving it extra plus points though, and there were quite a few funny lines in it. Unfortunately, some of the good lines were ones which I've seen before, not wanting to sound like some statto because I can only put a name to one of them.
"We made love from 2:00am to 2:15, it was the night the clocks went forward."
"It's been so long since I've had sex I've forgotten who's supposed to get tied up." - Joan Rivers.
(Raising bare hand.)
"No, it's Sooty in the nude."
One thing I noticed was that the actors didn't try too hard to cover up their laughing, just like in the pub and home therapy scene.
Also, the girl who plays Maria is cute. 
