Take my words as critics to improve and not as me being rude because I have no other interest except helping you make a better game.
Idea: I've seen similar games in my phone, with the exact same concept but with a different POV. Adding some original ideas and features in it would make it more authentic.
Graphics and representation: In my opinion it is better to keep the same style. What I mean is, if you want to do low-poly then do everything low-poly. The sphere has smooth shading, trees are low-poly. The ground: I don't know for certain if you are using Unity's terrain or you have designed it with another program and if it is the second case you have more polygons than you need and looks like they are triangle shaped which is no good for performance. You can do a better job with the snow rather than the Unity's default sprites because it doesn't match the others. The UI can be fancier. I'm a fan of simplicity but the UI you are using is more default than it should be. Maybe try to put some other fonts and not just the default Arial.
Controls: To me the controls feel a bit weird I would suggest to try another way of making the rigidbody move.
I encountered couple of bugs.
- Playing with effects' slider messes it up and you see black shapes instead of objects.
- It started to end the game randomly without touching any of the trees.