The cannon post really is cool, and neatly greebled, too. Nice job with that.
As for the landscaping, it isn't as such that bad at all - leaving some bare ground visible was a neat idea - put as criticism I'd recommend higher height differences to make the shaping more visible. The edged between snow and bare ground are also unnaturally sharp, so using slopes, gradually lowering plate layers or just some 1x1 white bricks might be a good idea to make the transition look smoother and more natural.
Overall, however, I'd say it's well done for first attempt in landscaping.
By the way, even though the design of the outpost building is cool, it's also somewhat plain. Greebling and detailing are nearly always a good idea.