I had one of those. Good times! Also, came with a (treasured) spacefighting game on a cartridge (can't remember the name) and another - rather more strange one - on a listing, where you could run a (rather detailed) nuclear plant. Great machine ...
That is a great game! It was very influential too.
No scoring system, just a rank. I still enjoy playing once in a while.
There is a slow down that happens when multiple enemies are destroyed and the computer cannot compute all the particles.
Someone fixed it a while back and the game runs at a perfect 60/50hz. I played that and the game seemed stale, not "alive" like the original.
Same with an arcade game by Williams: DEFENDER. The slowdowns are awesome and add to the game experience in ways not really foreseen by the original creator.
