that was a pretty simple game(although i'm not an expert), but wasn't that bad, as a 48 hours-game-made, so it is acceptable
but the game does not evolve, no background changes, and no new enemies.
Just could be nice if the mothership evolves its looking after eating some
quantity of ships(like changing color, creating new body parts, mutating, get bigger, etc)
For the ones who are getting some problem with the 'difficulty level' of the game:
Try using your 'abduction laser' to destroy enemies incoming projectiles( the purple ones) and use other airplanes to deflect incoming missiles