Some small bugs to fix:
1. On the upgrade menu the upgrade on the bottom right does not have any description text.
2. Once a certain height is reached the birds cease to exist at the lower levels and as the player descends a menu pops up to submit the player's score. I feel that menu should present itself once the player has touched the ground after passing that height limit, not as he/she is descending.
This game is difficult & fun... the upgrades make the game work and I bet every1 will be happy taking out some of those dang birds! Fun game!