Cool project! Some of the music was pretty great, especially the ice level, and the art has a consistent style. It's a small detail, but i really like the three sprites you used for the main ship- the way its wings dip down or up based on movement is a wonderful detail.
The gameplay is a little slow for my taste, though; I think some more challenge, but especially less emptiness would go a long way. Maybe more of those landmark obstacles?
I almost didn't play long enough to get to the second level because i assumed on first blush that the game would be just like the first level all the way through. The second level was, honestly, much more impressive visually and in its music. If I were you, i would DEFINITELY lead with that level, or overhaul the first one. And maybe find a way to set expectations within the game itself? I don't know how many people read the descriptions for a game in-depth when they're just browsing, but i jumped right into the game and had no idea it had any extra levels.