Ok, reached the highest medal, in fact even above 400 points, time to write a review.
In fact I must say that reaching those 300 points has definitely nothing to do with any skills, at that speed it is just dumb luck, hit & hope etc. Even with max upgrade for initial speed reduction and 1/2 speed power up most of the time after you pass approximately 100-150 points there is simply no time for reaction not mentioning recognizing what is being written on the power up circles. So as I said before: hit & hope. Try rotating and hope you will pick a good power up :-)
To reach the 300 points medal you need some special circumstances: max upgrades for 1/2 speed power up duration, max upgrade for multi color cubes - they are extremely important, max upgrade for initial speed reduction (yes, those upgrades aren't endless) and... here is where ends what depends on you. Now you need tons of luck to pick enough multi color cubes before the game becomes impossible to control - the about 100 points borderline. I spent few hours waiting for this kind of a situation, but when it happened - at some point I had about 110-120 cubes.
About other things: I agree that the writings on the blue circles are very hard to read, they should either have a bigger/thinner font or they should be written using white letters maybe?
The 1/2 speed power up is useless at the beginning, because after you pick it it expires before another cube is being collected. of course later it becomes crucial. To make some improvements and not to make the game too easy: the upgrade effect could be reduced, but on the other hand the effect could be changed this way: instead of being cumulative in the matter of power (1 power up - 1/2 speed, 2 power ups picked - 1/4 speed) it could be cumulative in the matter of time: another picked power up would add the time of being active to the previously picked.
Nonetheless - it is a good game :-)