1.1 Update

Fixed a few known issues:

• Waves no longer ending after going back to the main menu and starting a new game
• Game ending abruptly after reaching 25000 kills
• Big Boom upgrade not allowing the player to shoot after acquisition 

Shields have also been rebalanced:

• Lowered recharge delay from 4s to 2s
• Increased recharge rate from 2 to 10
• Increased starting shield from 0 to 15
• Lowered starting health from 50 to 35

I also added a timer for better clarity on wave duration.