Hi @rasa, the 9 point calibration is certainly the optimum calibration options available.. however, when you run the “test and improve” option you should see how accurate the gaze is across the 9 points. So long as the larger circle denoting gaze data is reasonably within the centre of the points on screen, then you should be assured that your device is accurate.
@grave, Sorry to hear you have not had an optimal experience with our eye trackers but it is worth bearing in mind that there will always be a limit to how accurate any eye tracker can be. This limitation is not technological but biological. Whilst you could look to an area ->()<- a couple of centimetres to either side, your eyes would in fact not move, this is the nature of human vision. For the eyes to physically move and hence be detectable, a sufficient distance between stimulus needs to be present, which naturally limits our ability to improve accuracy. Any increase in calibration points would not resolve this issue.
For an optimal gaming experience with eye tracking, this requires the game developers themselves to integrate the technology accordingly, which is why we have the Tobii GameHub that showcases the best of eye tracking in gaming. I would recommend you petition the developers of the game in question you intend to track with to include support for eye tracking in future releases.