This is a great game with smooth screen transitions and overall matches the theme perfectly. You did a great job, bro. I really enjoy the physics when you land on a mine and soar out into the sky; it reminds me of being hit by a giant in Skyrim.
With the fog in the background, the scene appears inviting (not too much and not too little just right just right). The gameplay is also extremely beautiful and easy, which is exactly how I like it, but I kept dying at first and wished for a rewind button like in Hell Gates, hehe. I've also noticed that the mines, cars, and consumables are generated at random, making the game less predictable.
One confusing aspects for me was when I decided to upgrade my motorcycle and couldn't figure out how to go back. Later, I noticed that the back button was located in the bottom right corner. (the button blended too well with the background i guess)
Final thoughts: You made a fantastic game, and I can tell you put a lot of good decision and effort into it. With the upgrade system, it contains massive replay value and I also really appreciate the game saves my upgrades and money when i quit and comeback later on. (Thanks for that) . The only improvement I can think of is a little more fuel and coin spawning, especially in the beginning.