Collect all trophies in game.
Complete mission with at least 2 cities left.
Complete a level by destroying all alien ships.
Complete mission with at least 2 turrets left.
Score 50000 points in game.
Destroy half the alien ships in game.
Destroy an alien ship with center turret.
Destroy alien ship dropping power up
Collect ammo power up.
Destroy an alien ship with right turret.
Destroy an alien ship with left turret.
Destroy bullet fired by alien ship.
999
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45531
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