I remember wanting to like Space Invaders, but the game proved frustratingly difficult for me. While I could score into the millions on Galaga, SI always wiped me out before the 2nd board was completed. I think it's the one shot at a time thing that messes me up. Galaga allowed multiple shots on screen at a time, but SI only allowed one. Plus, as you whittle it down to a partial row or two of invaders, their marching speed increases too quickly and I rapidly meet my doom.