Here's some advice, do what you want with them:
Is the game finished? Why the version number in the title and "Development Build" in the corner?
When the game ends, offer to "try again" or go back to main menu. You want your player to keep playing, so first option should be to play again as quickly as possible.
How about you start slow and everytime the player picks up a yellow you accelerate the speed of falling blocks?
Also don't get me wrong, English is not my first language either, but I suggest you ask a friend to correct your grammar.
You can improve this game! Good luck :)