The game is neat, I liked the concept of starting with a boss
but there are a lot of frustrating things
The boss' upper beam doesn't even need to be evaded while two other of his attacks are impossible to avoid. The medal for no damage, then, is just a matter of luck? I don't think it's nice to reward players for luck and game time. One can get a medal for playing for hours while a player was able to defeat him with almost no upgrade and he gets nothing. (unless it's that secret medal)
Plus there's this thing of the game freezing when when you dash to another screen or to the boss' orb. Another thing is that you can get a LOT more orbs from the first stage than from the second, that doesn't seem very fair.