Creating beautiful terrains isn't easy, especially in a game engine like Unity.  As an engine, Unity has many amazing features that make game creation a breeze. Moreover, I'd argue it would have been impossible to create Mars Commander as a one-man project using a different engine. However, terrain or level creation, is not Unity's greatest strength. In fact, without using specialized packages or other tools, Unity terrains will often end up flat and uninteresting. Therefore, we spent quite a bit of time getting our levels right. Mars Commander should make you feel like you're on a alien world, far away from Earth. 

Our first attempt at level creation used actual satellite data from Nasa, but that route proved unfeasable, since these the resulting maps weren't quite detailed enough. Subsequently, we started using stamps of terrains here on Earth, which led to a much better result.  

In our opinion, art should be based on reality first on foremost, not on imitating other art. This is why we used accurate replica's of real terrain instead of other means of sculpting. However, realism alone will not necessarily make for a great gameplay experience, which is why made our textures a tad more colorful than they ought to be. For an environment like that of Mars, this is especially important, as real Martian landscapes simply aren't vivid or interesting enough for a game, as you can observe for yourself in the video below:

Our color scheme is relatively simple and uniform as it consists solely of variations of the color red. Nevertheless, these colors are a bit more vivid than what you'll see in the video above. 

Another point important was our procedure of creation. While it is certainly still possible to create huge terrains by hand, it is a long procedure that is quite difficult, unless you're an experienced artist who knows exactly what he is doing. That is why we opted for Gaia Pro,  the immensely popular terrain and world-building tool, which you can find out more about here: https://assetstore.unity.com/packages/tools/terrain/gaia-pro-2021-terrain-scene-....  A tool like Gaia makes it possible to generate terrains using procedural techniques, which is exactly what we needed. You simply put in the rules that you want/need, and the program will take care of the rest. In all honesty, it was still quite the upward climb, but we're pretty happy with the result. 

You might expect an environment like that of Mars to be easy to create as it obviously lacks the vegetation that we find here on Earth, but that has not been our experience. In fact, one could argue that this type of environment is more difficult to produce for precisely the same reason. All you have to work with are your textures and your rock assets--that's it.  Good luck creating beauty out of that.

Shaders are a means to render your graphics in certain ways. Many games these days make use of cell shaded graphics, for example, to make the player feel like he's in an actual cartoon or Japanese animation series. Specialized shaders exist for Unity terrains as well, and for a project like ours this was a must. In particular, we opted for this one: https://assetstore.unity.com/packages/tools/terrain/microsplat-terrain-collectio...

Using Microsplat, we were able to create levels with many more layers than you'd normal find on a Unity terrain. For example, we were able to simulate rolling dunes of sand and a layers of small pebbles above more  foundational layers of coarse gravel. 

In art, simplicity is often best, so we didn't want to go overboard with specialized techniques or details.  In fact, our final maps use only four different base textures, which is significantly less than you might expect. We have rocky soil,  coarse gravel, sand, and cliffs-- that's it. 

In all, the process of terrain creation has been quite intensive and tricky, but many players have given us positive feedback on the end result, meaning we were probably able to get something right. 

With regards to the future, we feel we have an extremely solid foundational layer upon which we could build, meaning environments other than Mars are a real possibility.  It is something to look forward to.