So I played Condor Attack for you. This is what I found. A and B determine whether your ship is large (A - harder) or small (B - easier). Game select lets you choose if you want to fight Condors, Spiders, or Bats. Spiders and Bats are significantly harder than Condors, but I'm not sure Bats are harder than Spiders. Each time you clear a wave (level) the enemies are worth more points.
Interesting side note. If you switch difficulty between games without turning the console off, your ship will go back and forth in size as you play.
Vulture Attack is identical, except I'm assuming they call the first type of aliens Vultures instead of Condors.













