Exposition makes for terrible story telling, eitje, and I am offended that you would suggest that I was asking for more of it.
The weapons in the film looked like something a 9 year old would draw, as has been pretty standard in sci-fi for decades. Clunky, ridiculous crap.
The idea of a race that can travel the stars being stupid enough to make their weapons use some sort of DNA reading grips in place of a safety is ass. This would make the weapons useless to themselves if they were wearing any sort of protective clothing (like, you know, a space suit), while all all it would take to turn their weapons against them would be a few scraps of their own flesh. The plot element, that the weapons were rendered useless to humans, could have been done much more elegantly by simply having the weapons require the proximity of some sort of bracelet to fire. Something the alien leadership would have issued only to its security personnel. Something that might be stored, say, in the lander. This would also have covered the gaping plot hole of the aliens never using their own weapons in self defense, despite some of them being willing to tear people's arms off.
And the lander, a trans-atmospheric skiff, running of a little canister of brown goo? That turns you into an alien?
This kind of stuff isn't the work of a greater imagination, it's the work of a lazy imagination.