1.69k is my max height, 2k seems optimistic. This game reminds me of the paper plane flash game. Good work on handling physics, it feels good to fly.
The font is hard to read. For title, buttons, and headers that would be fine. But for labels and long messages, the font should be easier to read, even the common Arial font would do fine.
The ambience and sounds fits all together just right for the game feel. Overall, well done.
EDIT: Also the upgrades section needs a rework, it was confusing to interact. A simple + button next to the bar will be more understandable.