That's a lot of work you did in 7 days and the results look incredible. You even managed to implement ship and planet upgrades. The visual effects are beautiful. The sound effects were good. Everything was so highly polished. I don't know how you managed it!
The difficulty curve seemed rather steep. Games should start off easier and ramp up the challenge, otherwise you risk frustrating gamers. Buying an upgrade removes the previous one, that should have been made clearer.
Overall, a very impressive entry.