Results so far: From a usefulness perspective at the moment the big buttons are the most ready parts (driving around the world on a wheelchair in use), but have little to do with the intend of "haptic" games due to the original personal photonics project. The scorecard gets also good feedback, but the last version still needs testing on the long run if it works as intended.
The water gun might become interesting, at the moment we are using (and built) them for ourself, might be interesting if there is an actual more "serious" use case... as serious as one can get with a water gun :)
While pong on the belt works nice, buyilding it just for ithis purpose is overkill (there the 1D-games might be easier to built and use.
The construction game pieces fail due to stability issues or (when cirmcumventing these throug bigger build size) space constraints, while memory is not as funny as intended (as one could have already known beforehand).