Hello
First, I am more than intrigued with this idea, and have been mulling it over in my head a bit.
I have an idea to solve the hit point system issue. This may not be feasible the way I see it, but I am throwing it out there to see if it might work.
I am just riffing of the top of my head, so if I am wrong on certain details, please correct me.
What about using real laser pointers as the laser?
Each player would have to wear glasses to protect their eyes (if they even make glasses like that, but it seems I have seen such a monster before)
for the hit sensors, What about arrays of LDRs with with a light diffuser in front of them. wouldn't the diffuser screen spread out the light beam from the laser enough to effect one zone of the LDR array, and the drop in resistance could trigger a point value to be sent through blue tooth to the shooters unit and add to his XP and level.
With an actual laser beam, you could keep the keep the area of the target affected much more precise.
I am not sure if this would work or not, but it sounded workable in my head and I figured I would throw it out there.
Hope it helps
N8