4 and 8 would work better as GIFs since Cat-Powered UFO has some really good character and enemy animations. As for regular screenshots, I thought 5, 6, 7 and 11 (counting down from the top) were really good. Lots of color and action.
I would not recommend any extreme close-up screenshots like the first two, because then people can start to scrutinize the pixel art and it makes the game look more lo-res than it actually is.