Hey, sorry for the late reply. If you filled them in and you did not hear a "ping noise" that would be why. It just means you need to fill it in a small amount more. It's a bug that it shows it fill in early sometimes.There's a lot more to the game if you get past that though! :]
Crouching is not part of the game, but we will consider adding it. It isn't really mechanically relevant to the game, so we're hesitant to add mechanics that won't be useful.
We'll also consider adding the ability to grab the ball to make it easier to manipulate.
Vsync will come with time, this is just a demo.
Thanks for playing and thanks for the feedback!