I have only played 2 games so far. The first took 16hrs (2 x 8hr sessions over 2 days). The second took 6hrs.
I am wondering if this is normal & how people can manage to play under 4hrs? If its a 3hr-4hr game I am super happy to spend the evening on it, but when I start at 7pm & finish after midnight we are struggling with motivation.
I realise there is a lot to keep track of & probably gets faster with experience. But after the 16hr session I think we really covered almost every possible question & rule look up. Tonights session seemed pretty speedy through the turns, but it just went on for ages. I think what is dragging most is gates are always surging. We are on 4-5 gates open all night & they keep surging. The doom track doesn't advance.

Are there any tips to reduce the play time? My wife & I love the detail & depth of this game, but time wise I think my wife is not going to want to play again unless we can find a way to speed it up.
oh, we are playing 2 player.

Thanks all!

"how people can manage to play under 4hrs?"

By playing more.

"probably gets faster with experience"

That's absolutely right. 90- 180 minutes (Depending of expansions, if you want a short game try King in Yellow Touring Performance.)

How many rounds you've played? (count the mythos cards at the end of the game)

Longest game I played was Tsaghoggua, 31 (worst AO I think). shortest one was one absolutely brutal Yog Sothoth game, 6 rounds.

Shortest King in Yellow game 8 rounds. Shortest win was againt Yig, 8 rounds + final battle (yes, it's a win, not a draw...It was a bloody battle. hah)

" I think what is dragging most is gates are always surging"

Sometimes gate surge is good a thing, even two or three in a row. This is a "problem" which goes away the more you play.

Are there any tips to reduce the play time?

Close AND seal gates. Or go for the final battle (leave gates open/only close the gates).

Yeah, my games usually last 90 minutes (not counting setup of course), so, it's just a question of playing and focusing on tuning up strategy. Core set games tend to last ages because they board dries up from clues: save the one you have for seals.