Something's going on with the scaling of the user interface. Like, okay, you didn't take into account my screen resolution (1280 pixels × 800 pixels), so most of the buttons are off-screen even when I'm in full screen, fine. But why when I zoom out (in my browser) do the buttons stay the same size?!?!? It's like the game is trying to make sure that the buttons are too big to fit on my screen!
As for the game itself, I think maybe the hitboxes for when the game considers you to be pointing at a shape are too small, especially the triangle.