Here is a little review I wrote for another site...I will add more about the specific ride experience when I have the time.
Shrek 4D is a very fun attraction, but I felt, overall, it fell short of being a well-themed, integrated attraction. Individual aspects of the entire attraction are very well done and very enjoyable. The pre-show is very funny, the moving seats are a riot and the actual "movie" is entertaining, but together they don't quite work together and ultimately made me find the attraction as being nothing more than "decent".
[MILD SPOILERS AHEAD] The pre-show sets us up in the dungeons of Lord Farquad's castle about to enter the torture chamber and is very well done. Yet, this entire premise is quickly forgotten and ends up being virtually a waste of time, since once we enter the main auditorium and the movie starts, the whole torture idea is never mentioned again and we are basically left just watching a Shrek sequel, in many ways. The pre-show ends up doing nothing for the main show. Another problem with the pre-show is its length with much of it being nothing more than a "Cliff notes" version of the first movie....which makes the pre-show less entertaining during repeat visits.
Secondly, the moving seats are quite surprising and were incredibly fun, AT FIRST. Unfortunately, the effect is used too liberally and unfortunately ends up being nothing more than a distraction....both from the loud "air compression" sounds the seats make, sometimes making it difficult to hear the rather lackluster sound system, and the physical jarring motion they do...in fact, the times the seats move seem random, adding to their "distracting" qualities.
The other 4D effects used are nothing new. In fact, the "spider effect" is rather lame as this effect was much more appopriate as used in the Honey I shrunk the Audience show at Epcot.
The pre-show room is well-themed, but the main auditorium is suprisingly sparse and rather bland. Perhaps this is a reflection of the disparities in the themeing of the attraction between its pre-show and main movie.
Shrek 4D is very fun and an attraction that I believe many will enjoy and is definetely an attraction that deserves to be seen....but it ultimately falls short in reaching the "overall" enterainment value that other 3D/4D show efforts provide, including Terminator 2: 3D and the new Mickey's Philharmagic at the Magic Kingdom