This was a really enjoyable experience! The mouse controls were surprisingly intuitive, and the graphics, while simple, do an effective job at both establishing a visual style and indicating what everything does. You were able to slowly introduce new mechanics to the player in a way where I could easily understand and pick up on them.
One problem I did have is my mouse would regularly run off the window frame, causing me to lose control of the ship and potentially fail the level. This would usually happen either when I was trying to do some precise flying along an edge (such as in level 12), or when I was trying to move the ship quickly across a large distance. But that aside, this was still a really fun and challenging game to play!