Have been galvanized into blogging on this by Paul Linford and apologies for the delay, but I do have a life outside the Internet ;)
In short it was excellent, the production team overcame the potentially difficult task of packing in the backstory of Life On Mars and how Alex Drake went into a coma in under an hour fairly easily. The characters were well written, although (and here is my criticism) they did overplay Gene Hunt being the saviour of the moment a bit too much, especially with the use of music. That said, his opening line was just pure Gene Hunt genius.
The knowingness Alex has of her situation also helps, as the production rightly assumes that we know that the 1981 she "inhabits" are full of "imaginary constructs". This makes things easier for the audience, although in following that line they do deviate from some small, but important plot elements in Life On Mars. For example, Alex is not in every single scene, if she was it would have added to the sense of her world being that of "imaginary constructs".
I did find throughoughly enjoyable though, and liked the sinister use of the Pierrot Clown and George and Zippy fromRainbow , children's TV characters (well Zippy anyway) who I detested at the time and still do.
In turn, that leads me to ask my readers and fellow bloggers a worthwhile question; What were you doing in July 1981? As for me I was just finishing my first year at Primary School, have a vague memory of watching Charles and Di getting married, and had Record Breakers, The Adventure Game, and Blue Peter as my favourite TV programmes.