This page will shed light on the weapons and how you can mix them up.
Elliot is Sam's sword. It's very powerful and good for close combat. Pressing the attack button will have Sam thrust and swing the sword. Pressing up and attack will perform an uppercut attack, and down and attack will postition the sword to damage anything beneath. Running with Elliot is pretty destructive.
Performing a standing beam blast over the Sword will charge it up. After a few seconds it will make a noise and glow yellow. This is the same as the Standard Elliot but deals out a lot more damage.
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Ki Powers allow Sam to pick up certain items and throw them around. You can pick up; Twaddle, UFO's, rocks, bombs, the hamsterball and Elliot. Throwing them down will give Sam a vertical boost.
The Rocket Launcher is a very powerful weapon. Originally designed and named "the boss killer" it can launch out small and large rockets which do a lot of damage. The Rocket Launchers biggest fault is that it cannot shoot vertically. Holding down attack will launch a bunch of small rockets, then the launcher will charge up, when fully charged letting go of attack will fire a giant rocket.
An even more powerful weapon; by performing a beam attack on the Rocket Launcher it will glow yellow. This lets you know it's ready. Holding fire now will launch a continuous stream of rockets.
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Launching a Ki attack on the Rocket Launcher will turn the rocket hole purple. Any smaller rockets now will home in on bad guys.
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By combining both Ki Powers and the beam attack on the Rocket Launcher, you get this weapon. It is insanely powerful, will launch a continuous stream of rockets that home in.
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The hamsterball is the most damage dealing item in the game. Hitting any bad guy will kill it instantly. It can be picked up with Ki Powers and moved around.
In Satan Sam mode, by launching a dark energy ball the hamsterball will jump in the air. Making the ball even more deadly.
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Fire Sam is very powerful. However, Fire Sam cannot power anything up. So it's limited to killing. Fire Powers enable Sam to fly, and can pick off lots of weaker bad guys in one attack. This us unlocked in the game and once unlocked can be activated at any time.
Satan Sam is unlocked late in the game. In this mode Sam sprouts wings which lets him fly around, the ground beam is replaced by a giant ball of energy which travels through walls.