After trying to do a run through the game, I've noticed that the enemies continue to spawn too frequently and too numerously.

Large, powerful enemies like the cruiser spawn fairly early, while destroyers spawn too frequently to let your defenses and economy expand. I've increased the cost to spawn them accordingly.

• Increased enemy price of Heavy Fighter by 66%
• Increased enemy price of Frigate by 33%
• Increased enemy price of Destroyer by 60%
• Increased enemy price of Cruiser by 66%

What these increases mean is that each enemy will spawn much less numerously and frequently than before. The price of enemy fighters remains the same, as I believe they are fairly balanced.