Onslaught

You can set a tank to self destruct by pressing A. When it explodes it may take out a group of enemies.
Hold B when firing the rocket launcher. 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.

Successfully complete the game under the Hard difficulty setting.

In addition to the three difficulty settings available from the start, there are two unlockable difficulty settings.

Here are some tips and tricks from the developer:

1. Destroy the Hives - enemies will continually spawn from these locations - shoot them up and shut them down!

2. Become friends with your shotgun - while it is weak at a distance the alien bugs like to travel in groups. Rush up to them and take out a group in a few shots!

3. The laser whip is your friend - In the off chance that you run out of ammo or merely want to conserve it, the laser whip is your best bet. It never runs out of ammo since it recharges and is great at taking out enemies in groups of three.

4. Mission 2 Hold the Line will be your first big challenge. Stay cool and keep your distance from the hives. Remember, enemies will come out of the hives at a faster rate if you get to close!

5. Use your radar! Baddies will often flank your squad so be on the lookout for those little green dots!

6. Aim for the gutty-works! All the bugs have a weak point, indicated by a glowing mass on their body. If you hit that area you will do more damage and clear out larger groups in a hurry.

7. Don't be a hero! Sometimes the best strategy is to let the bugs come to you. This way you can pick them off from a distance without having to worry about taking damage from their corrosive blood.

8. Mission 5 is another tough one. Remember your training - let the bugs come to you. Once you have dispatch a wave, go around and take out the bugs blocking your radar. If you need some help, jump in the tank and use it like a turret.

9. The tank can be set to self destruct at any time by pressing the A Button. This can take out a lot of enemies if the situation becomes that dire!

10. Don't forget to hold down the B Button when using the rocket launcher! If you hold it down, then aim at multiple enemies, you'll fire several rockets. This is great for clearing out groups of enemies quickly!

Destroy the hives as soon as possible, as enemies will continuously spawn from them.