Onslaught
Successfully complete the game on the Hard difficulty to unlock the Expert difficulty.
Successfully complete the game on the Expert difficulty to unlock the Ultra difficulty.
Successfully complete the indicated task to get the corresponding weapon upgrade. Each weapon has two upgrades that are treated as additional weapons. They can also be used with a new game on the same saved game file.
- Assault Rifle level 2: Obtained from box in Mission 5.
- Assault Rifle level 3: Successfully complete the game on the Ultra difficulty.
- Grenades level 2: Successfully complete Missions 1, 2, and 3 on the Normal difficulty with an "S" rank.
- Grenades level 3: Successfully complete Missions 1 to 8 on the Hard difficulty with an "S" rank.
- Rocket Launcher level 2: Successfully complete Missions 9, 10, and 11 on the Normal difficulty with an "S" rank.
- Rocket Launcher level 3: Successfully complete Missions 1 to 12 on the Ultra difficulty with an "S" rank.
- Shotgun level 2: Obtained from box in Mission 11.
- Shotgun level 3: Successfully complete the game on Expert difficulty.
- SMG level 2: Obtained from box in Mission 3.
- SMG level 3: Successfully complete the game on Hard difficulty.
- Whip level 2: Successfully complete Missions 5, 6, and 7 on the Normal difficulty with an "S" rank.
- Whip level 3: Successfully complete Missions from 1 to 8 on Expert difficulty with an "S" rank.
- Assault Rifle level 3: Successfully complete the game on the Ultra difficulty.
Destroy the hives as soon as possible; enemies will continuously spawn from them.
In Mission 2, keep some distance from the hives. Enemies will spawn faster the closer you are to them.
You can set a tank to self destruct by pressing A. When it explodes it may take out a group of enemies.
When firing the rocket launcher, hold B. You can now target several enemies and fire multiple rockets.
Use the Laser Whip to save ammunition. It recharges and will not run out of ammunition. You can use it to take out up to three enemies at a time.
Although the shotgun is less useful at a distance, you can take out a group of enemies by rushing them and firing a few shots.
In Mission 5, let the enemies come to you. After destroying a wave, go around and take out the enemies blocking the radar. You can also use the tank like a turret if needed.