This ties in with what they posted on Instagram today.

For those who may not have seen, SouthParks has a review from the first day of Howl'o'ween 2018.

I visited on the first day of the event on Saturday 13th and have to say I was quite impressed. Creepy Caves surprised me with its intensity, and easily beats some of Thorpe's offering! There were sections of the maze which were genuinely disorientating, and meant I was never quite sure where the scare were coming from next. Curse of the Lost Tomb was fun, not the scariest, but that is to be expected for its target audience. Trick and Treat Woods was a nice surprise and contained a range of interesting characters, although was better after dark.

I was also impressed with the live stage show in the Gruffalo Arena - it featured some great dance routines, and the male lead had some particularly impressive vocals. Perhaps the only thing missing was some roaming entertainments to add some atmosphere in areas like Market Square.

I would have to agree we went for Howl-o-ween and we thought they had got the balance right. Like you say the show was great along with the Creepy Caves. I went through with my son and his mate although they where scared out of their skins, they did admit to really enjoying it, and when we left around the exits they did have roaming actors interacting with the crowds even blacked hooded caped demon actors that were joining in with the kids flossing with was quite amusing. Well done Chessington this year!

It’s a very interesting thing! Out of all the places to bring back something like this, I am hugely surprised it’s Chessington. I suspect it will be a bit like going through Thorpe Park’s mazes in normal mode, but it’s still great to see a more adult version of Creepy Caves happening. I may have to squeeze in a visit to a Chessington

So, Creepy Caves After Dark. That was... something.
After the announcement in the summer, it seemed safe to assume that Chessington's attempt at an "extreme" attraction was going to be more akin to a run through of Sub-Species, but what was on offer was far more intense! Entering, we found out that this really wasn't something you'd expect from a family park. Right from the word go, everything is crazy, with constant contact and a very sweary dialogue. The next 10mins was a constant onslaught of terror, and really gave a taste of what hell might be like. Nothing was off the cards here- the contact was far more extreme than anything I've encountered. To give an example- I was shoved into corners, forced to wear a hood and slapped. It was insane.
I really, really enjoyed this experience. I wouldn't say it was scary, but just pure fun- I was in stitches! It was so crazy to see that of all the Merlin parks, it was Chessington- the family park- would offer something so hectic and wildly innappropriate. The nature of the aggresive and continuous contact certainly means it's not for everyone- but if you enjoy things like Sub-Species, then you're bound to love Creepy Caves After Dark. I think my only concern is that the age restriction seemed very low- it was a little concerning that you only had to be 13 to enter, when it felt like something that should've been restricted to an adult audience. But as long as you read the waiver carefully and are prepared to be jostled and bitten, then by all means go for it.