Defeat the giant spider.

Keep your accuracy higher than 70%.

Finish a zone without losing a life.

Complete all underground zones without using a continue.

Kill more than 85% of the total enemies in a zone.

Finish a zone without using grenades or nukes.

Finish a zone in Co-op mode.

Finish a zone in less than 15 minutes.

Finish a zone killing less than 50% of the enemies.

Max out all of the vehicle power-ups.

Finish a zone killing 60% of the units on foot.

Complete the game.