This is a very cool game, there are so many levels and the idea is incredible.
Some things:
I do agree that the screen is too small. And the main menu is quite busy, maybe that's would be better when the game was bigger.
It took me a bit to figure out what bead is currently selected (probably also fixed by screen size).
I don't know if that is supposed to happen but I can keep shooting the last bead even if i have none left.
Sadly I don't know why but one time I killed all enemies but the door didn't appear.