They’re both fantastical non-reality settings where magic may or may not be real (but probably is).
For a long time I was a bigger sci-fi fan than fantasy, though I never viewed them as mutually exclusive. And I’m sure there was a time that I didn’t really think of them being separate things. I’m pretty sure my perception of these things was a fiction/non-fiction viewpoint.
With modern Games Workshop games, the line has really blurred. A picture of a GW game table could really go either way. It takes closer examination to make a sci-fi/fantasy determination.

<– Here’s a typical scene
There’s power armor, blasters, monsters, mysticism, and an otherworldly landscape.
To the uninitiated, this sure could look like sci-fi. But no! It’s fantasy! …with blasters and power armor…
So, I’d say that what Games Workshop is doing now very much blends sci-fi with fantasy. That’s probably smart considering how immensely popular 40k is. GW didn’t have to kill off the 40k setting and start a new IP line with their genre-defining flagship. They did do that with their fantasy battle line though (for those that don’t know). Maybe GW’s thought is that they would slip a little more sci-fi into the fantasy game and see if people like it.
If I had to pick, I suppose I prefer fantasy without firearms. Seems more medieval.
And as sci-fi goes, I’m OK with magic existing. That doesn’t bother me. That’s one of the early tenets of 50s-60s sci-fi; some things just can’t be explained. Also, you might encounter something so fantastic that it might as well be magic.
So what do you think about this one, sci-fi or fantasy?
Answer: Sci-fi
Ok, here’s another. Sci-fi or fantasy?
Answer: Sci-fi!
Last one, sci-fi or fantasy?
Answer: Sci-fi!
Just kidding! This is a fantasy set.
So there you have it. How much difference is there really?



