This is great! Gameplay is good, graphics are excellent. Flashing the path of oncoming enemy ships is a nice touch, as is the upgrade tree. Both 'main' paths are fairly balanced. I also really liked the touhou-style graze mechanic, which is not commonly seen in flash shooter games.
Medals-wise, so far 'all in a line' and 'the overlook' do not seem to be working, you might want to look into it.
One gripe, though, is about the boss warning sign. Yes, putting in some words in a foreign language might seem exotic to you, but they are just nonsense words. At least take the trouble to put them through google translate and make sure they at least make some sense. What you're doing reeks somewhat of snobbery and is incredibly annoying to anyone who understands that language.