It would need some tweaking to be an actual game. BTW - I only tested it on level 1. Got through it, and I think the next two levels add a bit more difficulty. It's been so long since I've played the real Space Invaders, on an Atari. I think there was a bonus for each time you blew up the mother ship, and probably a set number of points for each alien fighter destroyed. I believe the game also had three barriers you could hide behind, but they were progressively broken apart by alien missiles. I can't remember if they regenerated or not in subsequent levels.
Anyway, if I had to give this thing a name, I'd guess I'd call it, QB64 ASCII Invaders
Pete