Those last landscapes have a strong focus area. Although it might not have been intended, I like the idea of a dying-zebra-facility. The landscape around it too obviously embeds it though, wich seems a bit unnatural. The surface of the water on last one's cool but with more horizontal wave, reflektion, glitter-stuff on the surface, it should work better.
Like the more curved/ organik feel to tha last vehicle concept. Since to my unscooled eye your vehicledesigns are quite a blast already, I would sense somewhat of an challange in doing organic, curve and sphere- heavy designst. Like of a squid-tank or a monowheel-snail-racer.
Good to see you work on charakters too.