Air raid is the first of the missions for Zero. To trigger it you need to purchase the property marked with the ‘Z’ for $30,000. When you next save the game you’ll receive a call from Zero asking you to head over to visit the premises.
When you enter the shop, Zero is in despondent mood, as his geek rival Berkley is back in town and causing him grief.
You head up onto the roof where Berkley has launched a series of mini planes to bomb Zero’s transmitters. Seriously.
Use the mini gun to fire on the planes. Thankfully, there is unlimited ammo, but make no mistake this is hard work taking out all the planes. The planes usually come in from the left and sweep left to right and then if still flying right to left.
Try to fire on them when they are grouped together as it will be easier noting the trajectory as they sweep in from right to left. Keep an eye on the radar to check where and when they are coming from.