Great work! First thing that stood out for me was that the main menu is very polished and caused a good first impression.
I have two small feedbacks that align on the same problem: readability of the state of the game.
The first thing I was struggling to read fast was the direction of the player. The main bird is super small and it only turns in 8 directions. To aid in understanding the direction there is a small red arrow, but It was a bit too small for me. There were several occasions I thought I was in some direction to accelerate and go to another. Maybe It could be a thinner sprite, but longer and more transparent, so you can understand at a glance even with your peripheral vision. Making the player bird stand out from the other birds would help as well
The second is more related to the visual language of the game objects. Maybe items the player can collect could blink white periodically so it stands out from the enemies. I bumped into enemies thinking they could be collectibles and vice-versa. Also, the score numbers are red, so they kinda look harmful, so maybe change to white or some other color?
I think these two small improvements would make the game a lot easier to play. I love luftrusers so the game caught my attention, and looping around stuff is a cool challenge for this controls scheme.
Hope this feedback can help! Great job! o/ Cheers