The bazooka is a powerful weapon that you begin the game with. However, if you die, you will return with a standard gun. The bazooka fires wide shots that demolish weaker enemies in their path, but it has a slower rate of fire.
When you pick up the sword, you will hold it straight out in front of you. It will eliminate virtually every enemy that touches its blade. In addition, you can continue to fire bullets from your regular gun. The blade turns with you. Just don't rely on it against bosses.
Machine Gun
Boomerang
While the machine gun seems like a down grade from the explosive bazooka, its higher rate of fire makes it a decent weapon in its own right. Since it fires smaller bullets, it requires you to be more strategic when you aim.
The boomerang is a surprisingly useful weapon. It's not as powerful as the bazooka, but it flies forward before slowing down and returning to you. It is equally capable of destroying enemies on the way back, and you can throw several at a time.
Touching a lightning tile causes a storm of electricity to strike the entire screen, demolishing virtually every enemy present at the time.
Grabbing an earthquake tile generates a ground shaking tremor which startles the enemies present on the screen, and freezes them in place for a short time.
Bonus points
Power Armor
Points won't necessarily help you defeat the bad guys, but an extra one thousand points brings you that much closer to your next extra life.
While there are no vehicles in this chapter of Ikari Warriors, Power Armor provides a nice, if fragile, extra layer of protection against bullets.
Hidden sight
Protection fairy
Plenty of items are hidden below mounds of dirt and small objects. Collecting the sight icon allows you to detect where items might be hidden, although you can't see what they are until you expose them.
Collecting this extremely rare tile summons a fairy who protects you for a limited period of time by prevent your enemies from attacking you.
Power grenade
Key
You have unlimited access to useful grenades. But if you find this power up, your grenade blasts will be twice as powerful. You lose it if you die.
When you get sucked in through a dimension portal, you are forced to fight against a monstrous boss in order to escape. A key which allows you to return to the realm above is your reward.