Nice concept!

Nice to see another person using pygame :) 

The clouds and mountains are done well enough. Would be better to see some more types of attacks from the enemy. But so far looking at your code, it seems like you wanted to add some lasers or similar stuff, but have not incorporated them yet. But it is understandable given the time constraints. Overall, the game is nice :)

If you want you can check out my game and rate it, it is made in pygame too :)