BunnyFoot

A usability company who seem to do some interesting evaluations of games, and who have employees who've co-authored some academic papers,

@inproceedings{1462517,
author = {Tim J. Tijs and Dirk Brokken and Wijnand A. Ijsselsteijn},
title = {Dynamic Game Balancing by Recognizing Affect},
booktitle = {Proceedings of the 2nd International Conference on Fun and Games},
year = {2008},
isbn = {978-3-540-88321-0},
pages = {88--93},
location = {Eindhoven, The Netherlands},
doi = {http://dx.doi.org/10.1007/978-3-540-88322-7_9},
publisher = {Springer-Verlag},
address = {Berlin, Heidelberg},
}

Available from Springer with paid subscription

@article{1393920,
author = {Charlene Jennett and Anna L. Cox and Paul Cairns and Samira Dhoparee and Andrew Epps and Tim Tijs and Alison Walton},
title = {Measuring and defining the experience of immersion in games},
journal = {Int. J. Hum.-Comput. Stud.},
volume = {66},
number = {9},
year = {2008},
issn = {1071-5819},
pages = {641--661},
doi = {http://dx.doi.org/10.1016/j.ijhcs.2008.04.004},
publisher = {Academic Press, Inc.},
address = {Duluth, MN, USA},
}

Their website talks about engagement, eyetracking (Tobii), biometrics (GSR, HR, and "face tension and muscle tension"), advertising, "emotive engagement model", "quantitative and qualitative", heatmaps.

"Games testing: engagement and in-game ad effectiveness
A recent addition to our testing portfolio - we user test games for usability, engagement and also for the effectiveness of in-game advertising.
Using our specialist lab setup we record the players' eye-movements, and also physiological responses such as heart rate, breathing rate, muscle tension, pupil dilation and stress levels.
This lets us identify key episodes within a game that are creating the psychological responses you desire."

They have offices in London, Reading (admin only?) and Oxford, but it sounds like Edinburgh is the one for games testing.

They link to a few articles, including
Bang! Bang! You're Branded
by Steve Smith, Friday, December 22, 2006,

Bunnyfoot is Advertisers' Lucky Charm
David Radd on Monday, November 27, 2006

In-game ads: another perspective
Emma Boyes, GameSpot UK
Dec 11, 2006

In the comments section to that article BunnyFoot refer to using the PEEP ("Post Experience Eye-tracking Protocol") methodology. This is briefly described in a poster that has the BunnyFoot logo on it,

"PEEP is similar in principle to eye mark retrospections (Hansen 1990). Video replay of tracked eye movements act as a cue to retrieve thoughts that occurred during the completion of a prior task."

Video Replay of Eye Tracking as a Cue in Retrospective Protocol... Don’t Make Me Think Aloud!
Lizzie Maughan, Jon Dodd (BunnyFoot Managing Director and co-founder; DPhil. in Visual and Computational Neuroscience from Oxford University) and Richard Walters

Interestingly one of their employees, Aaron Young (head of usability, Oxford) used to study at Sussex on the HCCS MSc.