4DX cinema is programmed by a South Korean company, building on the older theme-park style immersive experience (I have memories of an Alien 4D experience at a Disney park in which you could feel the simulated breath on the back of your neck as the speakers in the chair implied it was right behind you), but expanded out to mainstream feature films. The chairs move, and various effects of light, water, fragrance, and air surround the audience in complement to the on-screen action.
Having recently moved out of London to the suburbs (greener, MUCH more affordable, ample opportunity to listen to podcasts on the rail commute), I find myself now living near the UK's first 4DX cinema in Milton Keynes. I went to see Ant-Man to try it out.
The effects were actually turned on during the Mission:Impossible Rogue Nation trailer beforehand, which worked quite nicely to acclimatise everyone to it and get the 'surprised' shrieking over and done with before the feature. However, the intensity of a trailer became quite overwhelming, with the motion effects struggling to keep up as we went from one action shot to another... and the effect of the pads in the seat actually beating you up was quite unexpected (and, again, cut very quickly in the trailer).
What works:
The motion on the flying sequences was amazing. It worked a lot like traditional motion simulators, except with a limited range of motion - albeit still quite a lot, and hot drinks aren't allowed in that screen for that reason.
The in-seat speakers were used minimally, for which I was glad - the movie's been mixed for a cinema auditorium, that's the version I want to hear.
The water-spray effects for each seat can be switched off at any time by the viewer, which I did take advantage of after a while. I live in England, if I want a rain effect I can leave the cinema and walk outside.
What doesn't work:
The air and water sprays are pressurised, which means that each time they release a jet of air or water there's a hissing noise. Sometimes this lasts for quite a while. It doesn't obscure the audio of the film, and it's usually in action sequences, but it is really distracting. Additionally, since 4DX films are also projected in Real-3D; getting specks of water on the glasses interferes a lot with the stereoscopic perception.
Fog (and I assume bubbles, although I didn't get any in my screening) is released at the relevant on-screen time - which means that it builds up over the next 30 seconds and then takes about the same amount of time to dissapate. Some of the screen is obscured, and the SFX/VFX people have already done their jobs in obscuring the action at the relevant points.
There's a vibrate setting on the chairs which kicks in at some really unnecessary times. During a normal driving sequence near the start of the film there was a low vibration throughout, which was quite distracting. It also seemed to be linked to the sub-woofer, so when a door closed or an object landed loudly on a table; the chairs would vibrate or even lift and drop.
Conclusion
The seat motion, when it worked, was a lot of fun, and combined well with the wind effect. Action sequences in motion and flying sequences were really well-choreographed, and didn't interfere at all with the viewing. A lot of the other motion effects could have been helped with a touch more subtlety and taking cues more from the image than the soundtrack, but that's perhaps down to personal preference.
However, at times, more attention was drawn to things by the effects than would have been in a non-4DX version, which is a concern as an editor - drawing audience attention is already such a delicate balance when editing, refined further in the online and mix...
The hissing from the air and water were the biggest distractions for me. Even turning the water off for my seat wouldn't stop the air, or the default settings for all of the other seats which were empty in the screen.
I've since seen Ant-Man again at a cinema screen, and couldn't honestly say that I missed any element of the 4DX. Indeed, it was a lot easier to focus on the film itself rather than having my other senses bombarded throughout - although it's not unusual to prefer a 'traditional' medium when meeting a new one for the first time.
Ultimately, though, I think the theme park is the best place for this manner of 'enhanced' experience.