Mr-FizzleHobbyist Digital Artist
This is a pretty appealing picture, at first glance.
The shapes are very smooth and easy to look at. Although he linework is slightly sloppy in some small areas, it still has that necessary sense of unity. The black shadows on the rocks and tank don't necessarily make sense in reference to where the light source is in the scene. The color pallet is very uniform and calm to the eyes. The design of the character and surrounding environment are also done well.
The largest problem here is perspective. With the character disappearing behind the horizon, it would make sense that the horizon of the hill be altered to focus on the character. Also, the grass and rocks stay around the same size as they move towards the bottom left-hand corner. This breaks any ability to have the interesting perspective that you were going for. They should be getting larger as they move closer to the viewer, therefore suggesting a 3-D space. You got both the perspective and clear light source right when you made the clouds, but that doesn't carry over to the rest of the piece.