Hi! Thanks for taking the time to play my game, it means a lot! Also thanks for a criticism, I agree the UI is terrible and some stuff isnt clear; ill release a hotfix later today that ought to clear some stuff up!
For now I may as well explain whats happening: The bottom health bar belongs to the boss, your health is the most left number on the top left. You can press space to dodge through bullets, dodging through green ones gives health. The damage you are taking is supposed to be a guided missle sort of attack, that homes in and fires after a second into more bullets. Its represented by a comically small shadow. This will all be addressed in the fix.
Stay tuned!