Much better than I expected! The intro sets the tone perfectly and made me invested in the mission. The music and sfxs were good picks and got me excited to shoot alien ships.
The art's inconsistent, but I understand it's hard getting assets from different sources that go well together. Those explosion animations were a really good choice, though.
I liked the final boss too. I think it's the right amount of challenge. I had fun :)
PS: With no Moon we're most definitely doomed even if the alien threat is no more :|