The Dungeons is good fun and probably the best done (can you tell I used to work for merlin? lol) it's very detailed and you can learn stuff while having a good laugh at the black humour they use, plus there's a couple of good rides in there too (credit?) I've not been since their new ride though. That said, it's not really a hardcore scare attraction
DON'T bother with Pasaje del terror, if it is still there? It's a waste of money, even if you haggle them down on their prices, I think we got in for £8 each and we still felt ripped off...
London Tombs I've not done so can't say for certain about that tbh lol
There's also a smallish one hidden down near the eye, but I've heard tell it's pants so probably not worth a look!
Hope this helped!