I'd re-enforce with some L brackets and the like. love the shape, very Taito-ish
are the green buttons for coin up? I know it sounds silly, but I'd keep them uniform, like green to the left and start to the right for both P1 and P2, its an aesthetics thing, symmetry doesnt always look better. Id go all red buttons for the players too, break up all that black and white a little and play off the color of the dynamite sticks.