I'm sure they do research like any other scientist hopes to do, but they might focus on North Korea specific things like coal chemistry (North Korea has huge coal deposits but very little petroleum, so coal chemistry has a niche there). They probably also focus on a lot of dual-use research like computer security stuff which can be done without having huge resources.
Contrary to popular belief, not everyone in North Korea is a sadist or a torturer, although most are totally indoctrinated into the system from birth.
An example: vinylon. [1] Briefly popular in the early 20th century, North Korea is about the only place in the world that still makes or uses the stuff.
It can be made from coal and limestone which are some of the few resources North Korea has. Similar to nylon or polyester, except stiffer. It's the material used for those shiny suits the North Korean officials wear. [2] A significant % of all clothing in the country is made from it at a couple big plants.
There is probably slave labour involved in its production. And yet one can say at the same time that, making Vinylon, in a very cold country, is probably significant and meaningful work for many of the middle and upper management and scientific types involved in it, yes.
Some models of how bad North Korea is (and it is hard to overstate, really, but some do) seem to require the North Korean people be almost inhuman in their endurance.
What's funny is that those extremely popular Fjällräven Kånken bags are made from Vinylon F, which the company strenuously claims is not of North Korean origin.
Contrary to popular belief, not everyone in North Korea is a sadist or a torturer, although most are totally indoctrinated into the system from birth.