* Weapons
1) Shotgun: Your default weapon, can fire suprisingly fast.
2) Spread Gun: Shoots waves of expanding blobs. Outstanding.
3) Laser: Hold down fire for a longer beam. Powerful.
4) Fireball: Fires spinning red blobs.
5) Machine Gun: Rapid fire bullets. Sounds like a drum machine.
6) Rapid: Speeds up shotgun, fireball & machine gun bullets. Handy.
7) Barrier: Complete invulnerability for a limited time. Nice.

* Use shots wisely: Jump shots and crouch shots allow you to attack while avoiding enemy attacks. Do not hesitate. Keep those shots going!

* Kill before being killed: if you see an enemy, shoot right away. Defeat them before they fire at you. Be the first one to attack!

* Tip for taking down the fortress: At the end of Stage 1 (the Jungle) and Stage 4 (the Waterfall), you will find yourself at the heavily fortified entrance of the next base. To gain access to the base, you will need to destroy the large sensor. The sensor in Stage 1 is guarded by a sniper and two mortar cannons, while the sensor in Stage 4 is guarded by a large five-way cannon at middle, with two rotating guns around it (one on each side).

* Tips for 3-D mazes: Destroy the orb-shaped sensors in each wall to stop the high voltage electric currents. Taking out the weak points quickly is key to conquering the 3-D levels before time runs out.

If you press the joystick upward and touch the electricity, you will be stunned and won't be able to move for a while. Don't move forward until you take out the sensor and stop the electricity.

After you take out the weak point, look at the map while proceeding. You'll know whether to go left or right.

You can dodge enemy bullets by lying down! Destroy rolling mines by using crouch shots.

As you proceed, there are weak points that are positioned so that you can't reach them. Utilize jump shots and crouch shots.

* Beware of falling off at Stage 4: In the waterfall, missing a platform and falling down will count as a miss.

* Barrier: The Barrier power-up can only be found at the beginning of Stage 4 (the Waterfall) or halfway through Stage 9 (the Hangar) if the player has only their normal gun equipped

* Rapid Bullets: The Rapid Bullets power-up will only appear in the beginning of the Waterfall stage and halfway through Snow Field stage (before fighting the first tank) if the player has only the normal gun equipped. Because of this, the only weapons the Rapid Bullets upgrade can be used with are the normal gun, the Fire Ball gun, and the Machine Gun.