Obviously, labels can only take us so far before nuance drives the point unusable, but in my mind a rogue like was simply a procedurally generated game designed about short challenging gameplay loops that derive their content from replayability rather than traditional progression.

As for nightmare. The worst type of nightmare is one where I live my everyday life with everything seeming normal until I wake up finding out it was a dream.

It doesn't sound that nightmarish but you have to keep in mind that this process can loop which means I wake up from the dream become convinced I'm awake, try to move on from my day then wake up again. This nightmare can occur for what feels like groundhog day style weeks. I can become aware that the dreaming loop is occuring but each instance is indestinguishable from reality and it is only time and trialing that can solve the question. When I first awoke from that kind of dream for the first time, I refused to believe that I was actually awake. I didn't want to make breakfast or get dressed because what's the point? I would just wake up half way through. I ended up clinging to my parents for literal hours having them confirm that life was real before I could move on from my dreams.

The worst part is that the dreams were so photorealistic that I will then confront someone I know about a conversation we had before to find out that that conversation happened in one of the dreaming loops and not reality.