So great but so rage inducing....
Well, I'm gonna start off just by giving a tip for people having problems with the boss fights. Phanto(or whatever he was called) is hard as balls to avoid, but not impossible. It seems like he picks an initial path towards you when he spawns, and then gets one chance to adjust his trajectory as he's moving. What I noticed is that if you just try to position yourself on the opposite end of the screen from where he spawns(he spawns near top, you try to move to bottom before he starts moving, and vice-versa) you can almost always dodge him as his vertical movement is limited and he will just curve around you. In some instances its almost easier to hang on the right side of the screen so he doesn't have time to turn towards you because he's already passed by the time he starts moving. However if you're at all close to in-line with him on the screen when he starts moving you're pretty much dead.
OK! Now that I have that out of the way... Graphics are 10/10. Music is 10/10. Presentation and concept is definitely 10/10. My only real problem was the boss fights. I feel like you didn't even play test them. I love a challenge so I HAD to take the key every time. The problem was that the reward wasn't worth it because the unlockable characters actually made the game HARDER to play, or at least I felt as much. Also, by the time i got to the 3rd boss it just starts to feel like random chance as to whether or not you get an open space to move through when you need it, and with as twitchy as the game is you're bound to slip your cursor out of the flash box occasionally, which makes your character stop, and almost guarantees death during bosses. In addition, I felt like the levels needed to be longer, they're about 45 seconds on average and don't leave you feeling like you accomplished much, other than memorizing the few obstacles in the 3-4 runs it takes per level to complete. All harshness aside, it is a GREAT game, you definitely put a lot of time and work into it. However I did have a bug with the checkpoint before the 4th boss, it would not give me the checkpoint if I took the key, but when I missed the key once and died on purpose to go back, it marked the checkpoint, which did not let me get the key again. I don't know if this was intentional or not but it caused me to stop playing for a while, I might pick it up again later who knows, depends on how fast my nerves calm down because the boss fights literally had me screaming at my screen. :P