It's Lava Bird.
Flying through lava caves. Chased by ice birds, I guess. Spits lava with every flap, an unfortunate medical condition.
- I made it in a day, with some refinements later.
- My high score so far is 78; I have not yet seen the last enemy in-game.
- Song is "The Final Boss" by @CandyDisturber.
- Everything else by me, @Unept.
UPDATE: I've added incrementing enemy difficulty. Beginning is a bit easier, but later on will be more difficult.