I would have preferred the level not to be randomised, I found myself resting until I found an easier one

I liked flying the Dragon, the glide felt super smooth right away. Also enjoyed the graphics, the dragon and the city background especially. I suggest you look into the Singleton pattern for your music player solution. It can persist even though the rest of the scene is reloaded, making the whole experience much more palatable for your players -- I agree with the others that this one change would make a big improvement for your game.

I feel like the music could probably be improved by having it continue after the player dies instead of restarting the music.

If me dying over and over again is your interpretation of Deja Vu, then mission completed. Go the flappy dragon, he looks cool. The music can get a bit grating after a few runs though.