Basically this is a mix of RIFTS and Shadowrun. You could have wacky civilizations in a post multiversal catastrophe, dimensional invaders and more. Or you can also tackle the situation of people from different dimensions trying to live together. All of these appear to be fine.

So this is sci-fi but with strong fantasy elements. Basically science fantasy but I like to use this term for something which is organized as a meld of the two from the get go, not being a chaotic mix.