It's one of the several games that have serious potential as a commercial game as it is. It can get crazy with horizontally scrollable and longer levels. Physics work smoothly as far as I could play. It's quite difficult as I couldn't pass Stage 2 even after 6-7 tries. I always end up falling down as I don't pay enough attention to the opened gaps while trying to hit the aliens above. Graphics should be mentioned as well. They look very cute and authentic.