This was cool, and evoked some Silkworm and slight Shadow of the Beast vibes for me!
A nice curation of a whole bunch of Creative Commons assets. Was the cover image/title screen background created for this project? It's a very nice piece!
I'm curious to know if the third ship design from the Frozen Moon sprite sheet makes an appearance eventually. I played for about 650m, but didn't end up seeing it.
One other thing to note is that your executable does not have permissions on Linux. It would be good to make a note on your jam page that Linux users will need to set executable permissions in order to run the game. This is something that is specific to Unix-like operating systems and their filesystems.
When loose files are uploaded to Itch, they can not preserve these permissions. When included in a zip file, those permissions can be preserved, but they can't be set from Windows. If you are on Windows and would like to try managing that yourself, I made a tool that can help with that.