Great and addictive game!
I really enjoy the novelty and elegance of your simple approach, 8-bit graphics and sound. Could have easily added more, but that's a trap many great game concepts fall into. What I think makes this "work" the most is the balancing of health total and regeneration rate as danger goes up.
For me, I found the best way to play to stay as calm, relaxed, and focused. My #1 priority isn't to destroy blue stars, that's my 2nd goal -- my main goal is to avoid damage. Third goal is to use spikes rather than seekers to destroy stars.
Currently I have the top highscore of 17,834,940 (finally beat yours, HybridMind!) but I see that easily being overthrown over time, being obliterated in fact. Currently have 14/23 medals, all but one of which are just for higher streaks & levels -- the one I think will be VERY difficult is the destroy 15 stars with just red seekers. Does letting a star supernova or accidentally body-ramming a star stop these counts for spikes or seekers?
I can't add many suggestions, perhaps make the health bar green or blue when it's at 100% so the player can easily tell. Right-clicking makes your dude freak out, but it's also disorienting and sometimes difficult to get rid of the menu, so not sure that this could be used as an "exploit" or not.
Most damaging encounters (each about twice as bad as the one before it):
Blue Star (and shrapnel)
Yellow Spike
Red Seeker
Also, I'm glad I checked out the credits :-)