One story element that has been in contention in fan discussions is the superweapon introduced in "Common Ground." The first point to usually come up is in relation to Quinn readjusting it. Many people rightly believe that Quinn would not have the knowledge to do this...but if you listen to what he says at the end carefully, it becomes a bit more believable. After the weapon self-destructs at the end of the episode, Quinn briefly mentions that he was only able to reverse the weapon so that it wouldn't affect human DNA. In essence, all Quinn did was do a simple reversal as he said...he made it where instead of destroying human DNA, the weapon would destroy all but human DNA. Even if the controls were in a foreign language, it is much more believable that he could make this simple change since almost all (if not all) of the Kromagg programming would remain unaltered. Also, once you listen to Quinn's explanation...you begin to feel sorry for the animals left nearby since they were vaporized along with the Kromaggs.
Another major point of contention is why didn't the Sliders go back to retrieve another of this weapon or at least info on it so they could beat the Kromaggs once and fall? This was explained in the Online Slide for the episode. In this information, we get a glimpse of what happened after the Sliders left. Apparently, the humans took the other prototypes and destroyed anything relating to the weapons and their design before the Kromaggs could get to them. So, if our Sliders went back, they would have found nothing to claim except for a likely swarm of angry Kromaggs. It is very likely our Sliders wouldn't ever risk going back anyway for that very fear of that highly hostile resistance when they believe they can get another just-as-deadly weapon from Quinn's "dad" with no fear of dying before they can use it.
Another question about the weapon is how many of the Kromaggs did it kill when it self destructed? According to the Online Slide, we know that at least all the Kromaggs on the base were vaporized...but if you remember from the episode, the weapon was set to kill every human on the planet. All Quinn did was reverse the outcome (not the programming), so in theory it should have killed every Kromagg on that planet just as programmed (along with everything else not human due to the reversal). That would be a huge shot in the arm to that world's resistance (especially with the event giving them access to all Kromagg tech including Manta Ships) and could lead to that world becoming a huge thorn in the Kromaggs' sides...well, at least until the humans of that world died from having their food chain irrevocably destroyed because of the disintegration of all animal life thanks to the "hero" Quinn Mallory.