Easiest way to win this game is to just blast into birds and die, quickly collect money and get the Helmet, once you've got this throw it on early and blast as far as you can until you die, and you'll quickly make enough cash to upgrade the Decrease the amount of birds. Get this up to the third tier and you'll be able to blast up (holding up and space) and activate the helmet just before you hit the third level mark. You'll have acquired enough momentum to shoot you up to the finish in less time than it takes for the helmet to wear off.
It would have been better if some of the final bosses attacks were introduced earlier on with previous bosses, but easier to avoid. Essentially a training exercise. That way you could at least practice a bit on the road to the final boss. I also found that when too many sprites were drawn that I had a lot of slow down which caused lag in the controls. I was able to get all the way to the end, with almost all the upgrades, but the bosses attacks made it near impossible to keep control without lag.
 "Up in the Sky"){kind=icon}
 "Reactance"){kind=icon}