First round against second stage of final boss: 2x full rage attacks, 2x normal attacks, energy attack and counter which did toggle, it still somehow got me to 22 hp? I suck.
Seeing previous comments, apparently this game can cause problems with latest flash? For me first race sort of starts, but with just black on screen, distance meter rolling to end and restarting, full turbo and 0 points and time not going.
For challenge 6... I'd like to underline the importance of completely dividing first big ball at begin... Worth it to train that part, you can even make it divide into small ones with driving it thru the edge of the screen at begin (instead of taking it to center, that seemed messier), if done correctly.
 "Terrascape")
 "Axon")
 "BioGems")
 "Neon Race 2"){kind=icon}
 "Epic war")
 "Crunchball 3000")
 "GlueFO 2.0")
 "Town of Fears")
 "Pandemic 2")