Imagedump incoming!
So I was playing this a bit more, and I figured I'd take the time to grab some screenshots to show. No Impostor screenshots though, sorry! :c
Captain Forever's the base game, and the free version. It's a bit aged compared to the others but still worth a play.

(Spaceship fight!)
Successor's basically Captain Forever
WITH LOTS OF FANCY NEW MODULES! that allows you to build crazy stuff like this.

(yes, and the highest level parts are rainbow)
Captain Jameson's slower-paced and revolves around liberating stations and stuff.

(Scrapyard! Here you can kinda see the part variety, although this isn't all the part types)

(And yes you can build giant-ass warships here too)
So yeah! Fun times.