Thanks! Yeah, this is an old one!
It is posted above that the second time I just cleaned and reseated the chips and that fixed the problem. It's been going strong ever since.
My high score is somewhere around 25k. I don't think I've made it past the blue background levels, and I usually only get to wave 5 if I'm having a particularly good day.
I've heard of people getting hundreds of thousands of points, which blows my mind. I wonder if the speed/difficulty stops increasing at a certain level. Do you know?
Wade