Thanks for playing. Yeah a good suggestion, it should be more obvious when the boss is defeated (he retreats and will appear again other levels). The player health bar is the amount of ether that has been collected. It acts as a shield but also makes you more powerful (rate of fire) and agile (tighter control of the broomstick). It depletes when hit but also each time you fire or use a spell (that wasn't implemented in time).

The idea of the mechanic is that the player has to be strategic in how they use the ether, rather than go gung ho they may wish to conserve their shots. When battling the end boss, you may want to mix up hitting the boss or going for the red ghost that are more likely to drop more ether. I would've liked to have made this more obvious with a tutorial or similar but time was just too tight!

Again thanks for the valuable feedback.  

Thanks for the feedback! i do intend to add more levels which will be tougher and more varied. Also, the balancing will be worked on too.

Thanks, glad you enjoyed it, I'll make sure to check yours out.

Thanks for the detailed feedback, I appreciate it. All valid points that I have noted. although the sloppy handling is by design, it tightens up as you collect more ether. You become more powerful and agile, but admittedly the balancing needs work.