Looks and sounds cool, but won't the enemies fire back? And where are the "bunkers"? 
I've started to work on alien bombs just yesterday evening. About bunkers I haven't yet decided if I want them in my game, LoL
The "Space Invaders Challenge" will end at December, 31.
By all means, do it your way. There isn't much point doing a straightforward Invaders clone, I think there are enough of those already in the world
I've had that idea for some time now, to make an improved Invaders, even before I head about that Challenge. Let's see, we have 10 days left. I'll have to think about it 
Wow, I'm glad you'll think about it! You can join the group for the challenge if you like 
Don't know if allowed, if not an admin can delete the FB group link, I'm fine with this 
https://www.facebook.com/groups/RetroProgrammersInside/?ref=...
Almost complete: still missing bonus UFO and, eventually, the shields (or bunkers, or whatever you want to call them). I have to set updated music and sfx too (both ready yet )