Gameplay
The biggest change of MP3 is the Wiimote + Nunchuck based control scheme. The previous titles never had a free look mechanism like Halo and instead opted for a lock on system. Prime 3 introduces a free look system using the Wiimote as a pointer on the screen. The Wiimote is responsible for aiming and turning Samus which is triggered when the pointer reaches the edge of the screen and "pushes" the view around. Running forwards, backwards, and strafing side to side is done through the analog stick on the nunchuck. You can still lock on to enemies which makes Samus stay focused on an enemy as she strafes around, freeing up the pointer mechanism to perform more accurate shooting.
Being the final game in the trilogy, Retro studios incorporates all the weapons and items from the first two Prime games, as well as abilities from the older 2D titles, and adds a few entirely new ones. One of the major changes made to the Prime formula is the stackable beam system. In previous games you could only access one kind of beam weapon at a time (ice, wave, etc) but now all beams are active at once removing the need to switch.
The visor system is still in place, however its importance has been diminished from previous Prime titles. Instead of being a requirement the visors are used to gain more information, and even unlock special items and bonuses.
Motion control gestures are used throughout the game in many forms. Switching visors is done by holding the Minus button and flicking the Wiimote up, left, or right. Morphball jumping is triggered by flicking the Wiimote up. Samus gains a grappling hook type weapon that is launched with the Z-button and requires you to "pull" the nunchuck to rip off armor and expose enemy weak points. There are also a variety of puzzles such as twisting keys and pulling levers that make use of the motion control.
Story
Metroid Prime 3 sees Samus exploring many more planets and areas than the earlier games. As a result there is a higher variety in environments and settings, however each individual area is smaller than before. Load times are still masked by creative use of doors and other transportation mechanisms, so the number of times you see a "now loading" screen is zero.
The game starts with Samus waking up from cryogenic sleep and being asked to help the federation in their fight. Samus is then thrust into her adventure where she encounters other Hunters introduced in the Nintendo DS title Metroid Prime: Hunters. Samus is also infected by Phazon, which allows her to use upgraded attacks at the expense of her health. And as per the name, the more Samus uses her Phazon strength she'll become more and more "corrupted".
The story is told through real-time cutscenes, fully voiced for the first time, and action happening around you during gameplay. Story details are also found through the visor system and scanning the appropriate items which will expose new information.
