This is good. I have a few suggestions, tho.
- The Throttle Up image blocks the view, hiding enemies and objects. Placing that on a layer on the back would be cool, but still allow for full viewing.
- At the end, there are replay and exit options that have to be clicked with the mouse. Making these selectable also with the Z and X buttons makes it easier to get back in the game quicker.
Good game. :)