Very good aesthetic, although I'm not really feeling the theme. I feel like I've seen several games exactly like this.
The level is also pretty uninspired, which is a shame because I feel it would be incredibly easy to make it better. For example adding some branching paths could add some much needed variation to the terrain, i.e. a choice to go underground or above ground. Maybe clouds that can be bounced on if you jump up from a mountain top.