I get the same feeling, Rob. There are times where I lose hours at a time, and i don't realize it. I'm a classic SS man at heart, but I just played an hour on Dr Who, and I kept going back for another game. Pinball does that to you - and it is great to step out of the "comfort zone" and play a different machine. I miss my Space Invaders, but I know it is in a good home and it is played often !
I still like the dmd's for all the missions to be completed and the skill required to max each mission, but you can just flip and still sometimes have a good scoring game. Do that on a SS and after 20 flips your score has increased by 50 points and you haven't heard a sound from the machine. You know that dead play where if it was a dmd, it would go into ball search mode. But usually on a dmd the ball floundering more times than not will fall into a scoop or something and a mode will commence.
