I got on this for the first time yesterday and was really quite surprised by, and impressed with Sub Terra. Though a very short attraction, the sum of its parts was well worth a re-ride in my opinion! Loved the lifts, thought the cavern was very well themed and (though I've never been a fan) the scare-maze really worked. It certainly did the job - everyone in my ride sequence left fairly petrified and there were plenty of screams - a great attraction. If I were to make any sort of alteration I would want the lights up a little higher when the seats fall, and for them to fall at different times, merely to build suspense for those yet to fall. The chamber was inanimate yes, and perhaps could do with just a projection of something moving to increase the level of threat, but realistically (ie not adding anamatronics / fire effects) I feel that those are the only additions that could improve it.