I was worried about it not being worth the cost of admission, but I'd definitely go again. The event started at 7pm and went until midnight and only guests with tickets for the party were allowed in the park. Everyone with those tickets had wristbands, and somehow the cast members managed to get everyone else out of the park. This meant much clearer walkways and a very short wait for rides like the Haunted Mansion and Star Tours. To be honest, I'd probably fork over extra money once in a while just to enjoy the park with minimal crowds (if I didn't have a job I'd be there on winter weekdays all the time).
That was one of the main perks of the Halloween Party, but there was more! These events are pretty much the only time that adults are allowed to wear costumes within the park. Kids can dress up any time, but it's more limited for grown-ups. Disney villains were stationed in several places for photographs and they closed the night with a farewell song by the train station on Main Street! I see the Evil Queen and Cruella de Vil around the park regularly, but they were joined by other villains I'd never spotted like Frollo from Hunchback of Notre Dame and Cinderella's Evil Stepmother and Stepsisters. So. cool.
And let's not forget the candy. Holy cow there was a lot of it. Trick or treat trails dotted the park, and each was marked with a giant ghost Mickey that you could spot and dash towards. They gave you a bag upon entering and mine was stuffed by the time I left. You received a handful of candy at every station and sometimes you got stuck with apples or carrots. The lines were all manageable and moved quick, and it was hilarious to see the kids get hopped up on all the sugar and come crashing down as it got closer to midnight.
I don't even want to think about how many candy wrappers the maintenance crew has to pick up after the Halloween parties. Yipes.
There were other little things too: the cast members who weren't operating rides had special Halloween uniforms, the Rivers of America were covered with fog, eerie lighting was rigged throughout the park, the castle was cast in a creepy light and had projections going across the surface, and there was a fantastic group that sang Halloween tunes while floating on a raft in front of Tom Sawyer's Island.
It was a blast.
I haven't trick or treated in at least fifteen years, and I had so much fun acting like a kid - more than I normally do. Other adults must get that kick out of it too because there were a lot of other childless ones there. And the cosplayer in me was impressed by the sheer number of people who arrived dressed for the occasion. I saw a few Doctors, lots of Star Wars and Avengers costumes - and I can't remember the others. Too much was happening for me to retain everything I saw.
I know it's too late for this year, but if you've ever considered going to the Halloween Party or will be in the area next fall: do it - it's a wonderful time!