This is more fun than it should be! I was a little confused because I thought red just highlighted which alien you were controlling when I saw prior videos. (Obviously not, in hindsight.) Space Invaders was always super boring to me so anything to mix it up is great.
I can imagine another experiment, in the historical fiction theme, would be a Space Invaders predecessor that played more like Missile Command. Still one tank (or whatever that is) with cover, but you shoot the missiles with their damage radius, and maybe the aliens have more effective weaponry as well?
The blast radius would be fun to see when the board is filled with aliens, and it would make that terminal scenario of chasing one elusive alien more fun. Games would be over faster too, I think.