In my experience the character artists were the go to artists for most things. If you could do characters it was kind of a given you could do vehicles and props. So naturally if you have the time and the motivation it would make sense to broaden your skills. But if you’re concerned with just pumping out a bunch of portfolio pieces, or you’re looking at a specific position at a specific studio that does environments, or architectural stuff as an example, then I would show off that kind of stuff. But if you wanted to take a broadest appeal approach, I would go for characters and throw in a vehicle or something hard surface to demonstrate the skill. So maybe try your characters and then your motorcycle. I don’t know if the game props on that page are really adding much but maybe someone wants to see it for technical purposes.
As far as your portfolio goes, I’m not sure if this is the final presentation but I would fancy it up a bit. Use images without weird shading or hard edges on your models. There are a few areas that could use another subdivision level. If you’re going with hard edges to show off polyflow I think wire frames or wire frame overlays would be easier to see but that’s your call.
As far as your art goes, it’s all pretty good. I like to see textured versions of everything but I don’t know how much people care about that. There are certain areas that look a little neglected. The feet on the statue, the skin on the lady, the shoulders on the robot, the hard surfaces on the hands of the demon creature. Some surfaces will have a lot of small texture detail, veins, cracks, wrinkles types of things, and then some surfaces will be flatter, where they don’t have details or the shapes are a little wobbly. I see the details but it looks a little inconsistent. They’re minor things but they’re missed opportunities to show off I think. The textures look good but the shaders look shiny/ plastic looking. There are certain things like the shapes on the demon dude and the ribs on the lady’s dress that look like a little bubbly. You could maybe sharpen it up a little more and make it a more obvious call out to some object. Something that clearly says, these are corset ribs or whatever. Again a nit pick. The faces on your two people look a little similar also. You might want to consider some more variability. If not in them, then the next time you make a person. I don’t know, maybe make a pretty lady or a rugged dude type of thing just to show you can visually express a personality. You have good stuff though so you’re pretty close.