I used the engine three times for scientific research and/or student projects.
The first time I used it in a linguistics course about symnolic and statistical text processing methods to visualize syntax trees in Latex-notation:
http://www.christian-behrenberg.de/work/SynView.html It is only a visualization tool but it was great for me to use Gamestudio in a serious context.
The second and third encounter was during my bachelor thesis research. I created a statistical Bayes-classifier with color histograms for CIE-Lab, HSV, HS(/V) and RGB colorspace(s) for skin- and non-skin color distributions from a huge database (Compaq Database, Jones/Rheg). To get a feeling, if I have done the code for building my histograms right I wrote in Gamestudio a parser and used the new particle instancing feature for this.
The only image I have left is this (I could generate new images of course, but my histogram data format changed from text to binary, since I didn't normalized them (for some good reasons) and therefore the files became VERY huge after sampling the whole database.. ~854 million samples for non-skin- and 80 million samples for skin-color-tupels!)):
The achievement of my thesis was an algorithm to derive the head pose of a single person in an arbirtray video stream and I used Gamestudio to sync and save my approximation (x,y,scale,rotation) during a video with a 3D avatar head for the final presentation at the institute I was working at.
So, nothing special. But as I said, I was very glad to use Gamestudio for other things than games