Version 0.5.0 Time Attack Mode is implemented

• Added time attack mode (will be available after defeating a boss once)
• Acquired upgrades can be checked (displayed on upgrade selection and pause screen)
• Revised enemy stats upward in line with the player's increased firepower with this modification
• Slightly weakened attack drones and barrel bombs

Bug fixes

• Duration effect was not reflected in the blast.
• The effect of Attack Rate in the store was reversed (the higher the level, the lower the rate of fire)
• Lasers did not always hit the enemy.