Your right about the X gun thing, thus explaining why it didn't kill the Tokyo team instantly.
Nurari doesn't seem to be capable of multi-tasking with abilities otherwise he would use the X-rifle theory of invisible blasts, the laser eyes, and become super strong all at once (before Oka, no sign of super strength was seen in my opinion because all he did was grab people or not touch the Gantzers but making them explode). Why is it that none of the Gantzers has tried using the X-Ray on the guns except for the one who confirmed he was the 100-pointer? maybe one of the other forms as a weakness in it? don't know yet though, hopefully something comes up in the sniping chapter.
A thought on his ever changeing abilties, the fleshless form or aka Skeletor form is known to move at superhuman speeds that out matches the Gantzers, possible ability to use explosions (leaning back to the X-Rifle/H-Gun theories) which is probably why the buildings exploded before Nurari returned, and breathing...was there any sign of Nurari breathing before since hes able to bend his shape and form at will? the only thing i found on him about breathing is when he laughs but that doesn't mean much. (yes i just disproved his inability to multi-task but since its only a theroy, the one above could be right). i believe you can see a heart to when hes skeletor on page 15-16 but its pretty useless since he might have the same organs as humans in all forms :\
^ But the x-ray doesn't really work to show weakness, I think the main purpose should be detect disguised aliens such as the statues. Aside of course from Oka spotting the spider-bull's brain, which wasn't really something miraculous, more like seemingly useless images to fill pages up, imo.
Also, right now, for instance, it's obvious they used the x-ray feature, since otherwise they wouldn't be able to aim and shoot Nuri. Now, Cherry's psychic scanning, THAT could work to detect a weakness, maybe, but it doesn't seem like we'll know, cuz he's being a dumbass this chapter.
And no, the skeletor form isn't known for that, and it's far from fleshless by the way, it's just theorized he landed a super fast punch on Kaze. Other than that we haven't seen anything really. And for the explosions, someone remarked it was more like those were an effect of the buldings collapsing rather than the cause for them collapsing, it's unclear though.
His breathing was also sort of enphasized when he used the other "demonic" form, behemoth. Actually, some (including myself) were under the impression the explosive attack he used on katou was connected to the breathing.
And as for the heart, yup, it's a heart. But is a clearly visible heart a possible weakness? My guess: no.
I seem to think Nuri landed a fast punch because I noticed a quick flicker with one of his arms just as Kaze's head spins to the right.
About Cherry scanning Nuri. It's a little too late now since he's probably too far to take a through look. It seem like he already scanned Nuri just as he turned into Diablo, but didn't really said anything to the group. Maybe Nuri has no internal weaknesses?
ok, kinda typed most of it blindly XD didn't check my own work but thanks for pointing out things i missed or didn't really look for.
Honestly, theres not much less regarding about Nurari unless you want to go into specific details, other than that than we've already discussed most of the main things about him/her/it.