When the first few waves of enemies come rushing at you, choose the straight laser as your weapon to take them out one at a time. Now quickly switch to the round vulcan missiles when the enemy ships encircle you. Dodge between the asteroids, and destroy the ones that shoot at you. To defeat the mid-level boss, avoid his fire and shoot him right in the center. Again, for the next wave of enemies, your best weapon is the straight lasers. This weapon is also effective for blasting through the purple webs in your way. When you reach the giant spider, switch back to the round vulcan and hit him directly in his blue eye. Avoid the bullets and mini-spiders as you fire away.