For everyone asking about how to get Excalibur. You need to beat level 19 with "Lightknife" (The very first weapon that you start out with). It sounds hard, but is really simple, because you should have levelled up gatling, and levelled up your attack shield and energy as well.
Not really sure why you're all complaining.
I got the badge first try.
The mothership is too easy, just kill the little ships as they come out and keep attacking the mothership.
Pechatnik, why do you think it's the U.S. force against Germany in a game called Warfare 1944.
Let me spell it out for you.
1944 = World War 2.
World War 2 = Nazis
Nazis = Guess what, GERMANY!
We can all learn something new everyday.
Oh, and as far as Loki goes.. just use any of the end game weapons in the Odin ship.
Circle around him nonstop and shoot.. overdrive whenever it fills.
If anyone is wondering about gold making..
You can go to the easy level 17.
You want a chain of 150k.
150k is where you get the +5000 gold.
Once you hit 150k, just get hit on purpose to reset the chain and get 5000 gold.
You can make an easy 50k-70k per run on that level.
Other than that, max all 3 stats to 99 for Axia.
Beat level 19 with the starting gun for Excalibur.