I now realise that there isn't too much to review on an episode-by- episode basis. And since I'm the only person who's going to enjoy reading these reviews in the future, I'll simplify my reviewing method (for certain titles) to a list of what I liked and what I didn't.
What I liked: The idea of mixing Kahlua and root beer, Marshall as Cher and his take on Ewoks, Barney's costume introduction, Barney's idea of having two costumes, the devil and the angel on Ted's shoulders, and Robin and Ted's conversation on the rooftop at the end.
What I didn't like: Lilly's Halloween costume, Robin's boyfriend trying to feed her, most of the rooftop party, and Robin getting territorial over ice cream.
What I liked: The idea of mixing Kahlua and root beer, Marshall as Cher and his take on Ewoks, Barney's costume introduction, Barney's idea of having two costumes, the devil and the angel on Ted's shoulders, and Robin and Ted's conversation on the rooftop at the end.
What I didn't like: Lilly's Halloween costume, Robin's boyfriend trying to feed her, most of the rooftop party, and Robin getting territorial over ice cream.