I made an absolutely stupid mistake which explains at least half of the negative reviews.
Enemy health was calculated 80 * (0.2 * player count). Yeah, player count. So if 1000 people played at once, enemies had over 200 health more than they should. It's fixed now.
Also other changes:
- Added Hong Kong region
- Improved enemy balance and power
- Added language dropdown at the start
- Increased turret damage
- Increased car durability