It felt like a 'webisode', Watson's stag night? It seemed out of place when you compare he previous two series. I haven't enjoyed this series as much as I thought I would, it's just not the same, there seems to be too much emphasis on fan-service and because I know that it is fan-service, it backfires for me and takes me out of the programme and I think to myself 'they've done that especially so that people will make a internet meme out of it". I wanted a 'serious' Sherlock episode and the drunken stupor humour just didn't work for me ("the games.. something" and "cluing for looks"). It felt more Harold and Kumar than Sherlock and Watson until the final 20 minutes.
I've seen it described as "drunken hopscotch" which sums it up, at times it was entertaining at others it was painful to watch but it gets the important plot points across to set up the third episode.