There's actually 121 Stars in the game, not 120. To get it, you must first have all 120 Stars. This unlocks Luigi. Beat the entire game with Luigi, defeating Bowser at the end. After this, a new galaxy will be unlocked. Finish this final galaxy to get the 121st Star.

Here's how to get Luigi. First, get all 120 Stars in the game. Then, return to Rosalina (on the Comet Observatory) and request to fight Bowser one last time. Defeat him and let the credits roll. Thereafter, a message will appear telling you Luigi is a playable character.

The Grand Finale Galaxy, which is the secret galaxy that can be unlocked after 120 Stars are gathered with both Mario and Luigi, holds another secret. Once the final Star is acquired with both characters in this galaxy, you will be able to see your death count on your save file. This will allow you to see how many times you died while playing the game with both Mario and Luigi.

If you have a second Wii controller, you can have a friend play along with you. While there won't be a second player on-screen, you will have a second cursor to use. This means that Coins, Star Bits, and the like can be collected by the second player. There's also some functionality in controlling Mario's jumps.

Because you start each game with only four lives (after shutting the game off and turning it back on), you might be in need of some extra lives upon rebooting the game. You can usually get five right off the bat from Toad (he'll run around with a letter above his head, symbolizing a letter from either Luigi, or more likely Peach). There are four more strewn around the Observatory that you can acquire, however:

• 1.) On the moving green platform below the core.
• 2.) Under the stairs leading to the kitchen.
• 3.) Right at the top of the observatory. (Once the Red Star is unlocked)
• 4.) Underneath the entrance to the gateway to the stars. (Once the Red Star is unlocked)
• 5.) Next to the StarShroom (in a crate)

Cheats are unlocked not by inserting passwords, but by acquiring the thirty Intel Pieces strewn throughout the game. The more of them you collect, the more cheats you can access. On the left are the number of Intel Pieces collected, and on the right are the cheats that are unlocked, with an explanation of what each does.

• 2 - "CoD Noir" Play the game in black and white.
• 4 - "Photo-Negative" Game colors become inverted.
• 6 - "Super Contrast" Game's contrast increases.
• 8 - "Ragtime Warfare" The game feels like an old silent movie.
• 10 - "Cluster Bombs" One frag grenade thrown equals five in explosion.
• 15 - "A Bad Year" Enemies explode into tires when shot.
• 20 - "Slow-Mo Ability" Game plays at 40% normal speed.
• 30 - "Infinite Ammo" Just what it says.

To unlock Arcade Mode, beat the game once through on any difficulty level. Arcade Mode itself is split into two options - Full Challenge or Level Challenge - that add extra replayability to the game.

To unlock Prestige Mode, which is a multiplayer-only mode, you must reach experience level fifty-five. Instead of capping out at level fifty-five, which is the highest level, Prestige Mode allows you to start again from level one. This can be done a total of ten times, giving you ten different icons in in-game lobbies to show your extreme achievement.

To play an all-new mission, which is an extra mission after the main quest is completed, beat the game and view the ending credits thereafter. After they've run their course, you will then be given the opportunity to play one last single player mission before all is said and done.

To unlock the following "Golden" weapons, fulfill the requirement listed.

• AK-47 - Complete all Assault Rifle challenges
• Desert Eagle - Attain Level 55
• Dragonuv - Complete all Sniper Rifle challenges
• M1014 - Complete all Shotgun challenges
• M60 - Complete all LMG challenges
• Mini-Uzi - Complete all SMG challenges

To unlock the following weapons in multiplayer mode, reach the numbered rank listed.

• Assault Rifle (G3) - Rank 25
• Assault Rifle (G36C) - Rank 37
• Assault Rifle (M14) - Rank 46
• Assault Rifle (M4) - Rank 10
• Assault Rifle (MP44) - Rank 52
• LMG (M60E4) - Rank 19
• Pistol (Desert Eagle) - Rank 43
• Pistol (Golden Desert Eagle) - Rank 55
• Pistol (M1911) - Rank 16
• Shotgun (M1014) - Rank 31
• SMG (AK-74U) - Rank 28
• SMG (Mini Uzi) - Rank 13
• SMG (P90) - Rank 40
• Sniper Rifle (Barret) - Rank 49
• Sniper Rifle (Dragunov) - Rank 22
• Sniper Rifle (M40) - Rank 04
• Sniper Rifle (R700) - Rank 34

Below is the level distribution list for Intel Pieces, which are enemy laptops full of information strewn throughout the game. There are thirty of them total. The left column is the level in question, while the right column is how many Intel Pieces can be found on that level. Levels with no Intel Pieces are excluded completely.

• Level 2 - 2
• Level 4 - 2
• Level 5 - 3
• Level 6 - 2
• Level 7 - 2
• Level 9 - 3
• Level 10 - 2
• Level 12 - 2
• Level 13 - 3
• Level 14 - 2
• Level 16 - 2
• Level 17 - 1
• Level 18 - 2
• Level 19 - 2