The use these codes, you first need to spell CHEATO, then enter the respective codes by shooting eggs at the letters. Note that the eggs don't make a sound when they hit the letters -- but you will get a confirmation noise once you have entered the whole cheat. Like with Cheato's cheats, you need to activate the codes by using the plaque on the wall. These codes are similar to Cheato's passwords, but spelled backwards (the original word is listed as a reminder): 

Gameplay Codes Code Reminder Effect 
SREHTAF feathers Doubles the amount of feathers you can hold. 
SGGE eggs Doubles the amount of eggs you can hold. 
FOORPLLAF fallproof You become immune to damage from falling. 
KCABYENOH honeyback Refill your energy bar gradually after taking damage. 
XOBEKUJ jukebox Enables the Jukebox in Jolly Roger's Lagoon. 
YGGIJTEG getjiggy Activates the "Jiggy location" signs in Jiggywiggy's Temple. 
GNIMOH homing Get homing eggs. 
 

There are also a couple of Special Codes that activate features you can't get from Cheato or by normally playing through the game: 

Special Codes Code Effect 
JIGGYWIGGYSPECIAL Opens up all worlds (Level Select Code) 
NESTKING Get infinite Eggs and Feathers 
SUPERBANJO Banjo will move faster. 
SUPERBADDY Enemies will move faster. 
PLAYITAGAINSON Unlocks all the cinemas in Replay Mode. 
JIGGYSCASTLIST Watch the cast list "Character Parade". 
 

Note: The last two cheats won't appear on the cheat menu.
 

Dragon Kazooie
Did you know that there is a way to turn Kazooie into a dragon? You will need the Ice Key, the Mega Glowbo and Kazooie's Talon Torpedo Move for this transformation. 

To get the Ice Key, go to the Jinjo Village area of the Isle O' Hags and head for the sandy area near the lower Jinjo Houses. Grip Grab the ledge that winds around the left side of the green rocks and enter the cave there. At the end of the cave will be the final Game Pak. Smash it and grab the Ice Key! 

Next, you will need the Mega Glowbo. Head to Gutter Gulch Mine, grab the Turbo Trainers (sneakers) near the entrance and go to the start of the river that runs through the level. Step on the switch to open the gate and follow the stream to its end (you can walk on water when you're using the Sneakers). Enter the cave and jump down to the very bottom of the cove. There is a boulder underwater marked with Kazooie's face that you can only open with the Kazooie Torpedo Move (press Z while you're underwater). If you've got it, you can bust open a tunnel leading to a giant ice door which can be unlocked with the Ice Key. Inside, you will find the famed Mega Glowbo. 

With the Mega Glowbo in hand, head back to Pine Grove (the Witchy World Hub) and pay a visit to Humba Wumba. She will now transform Kazooie into a green, fire-breathing dragon. Kazooie will remain in this form until you return to Humba Wumba and have her transform her back to bird form. Although Dragon Kazooie is virtually identical to standard Kazooie, she now has a handy fire breath move that you can use by pressing B. 
submitted by Franjo-Peerzooie
 

Mysterious Signs
Getting confused by the mysterious signs in Jiggywiggy's Temple? All they say is "When fortune smiles, here will be written the Jiggy secrets." There is actually a hidden room in this temple with a sign that hints at how to make the signs active: "Witchyword is where fortune may smile upon you." To see this room, simply walk through the mural behind Jiggywiggy. 

The solution is to go to Grunty's fortune teller tent. She will eventually give you the "GetJiggy" cheat (see Codes). This unlocks the signs in Jiggywiggy's Temple that give you clues about all the Jiggy locations in the game.
 

Character Parade
Once you collect all 90 of the Jiggies in Banjo-Tooie you will unlock a "Character Parade" mode for the "Cinema" options feature. Every character that appeared in Banjo-Tooie returns for an encore curtain call. If you don't have as much time as Fran -- but you still want to see the Character Parade, you can also use the JIGGYSCASTLIST cheat listed above.
submitted by Fran Mirabella III
 

Cheato's Cheats
If you’ve been paying attention to your surroundings while playing the game, then you should be actively collecting Cheato's ripped out pages. For every 5 Cheatos you collect, Cheato will tell you another cheat. To activate these Cheats you must enter them in at the Code Chamber in the Jade Snake Grove area of Mayahem Temple (must use Golden Goliath to kick doors to Code Chamber in). Anxious to see what you'll get? Then look no further. 
 

Feathers: This cheat will double the amount of each type of feather you can carry. This is particularly helpful when battling the bosses at Grunty Industries and Hailfire Peaks. 

Eggs: This cheat, like Feathers, doubles the amount of eggs you can carry. This will help out tremendously with Clockwork Kazooie and Grenade Eggs. 

Fallproof: With this Cheat activated you will not take any damage from falling from unusually high places. This will become very helpful when bounding around the summits of those Hailfire Peaks. 

Honeyback: The closest thing to being permanently invincible you can find. The Honeyback cheat will slowly and continuously refill your depleted energy bar. Very, very helpful when fighting Mingy Jongo and the Hag 1! 

Jukebox: Not really a cheat, but cool nonetheless. With Jukebox activated you can head back Jolly’s Inn in Jolly Roger’s Lagoon and use the jukebox to play any of the songs you have heard in the game. 

GetJiggy: This will make the signs available in Master Jiggywiggy's house. 

Homing: The eggs will home in on the nearest enemy. 

NestKing: With this cheat you will have unlimited eggs and feathers. 
 

Game Paks
In a couple of really well hidden spots lie Banjo-Kazooie Game Paks. Game Paks are little creatures that bounce around gleefully, trying to keep their contents away from you. Bashing them open will reveal one of the harder to find items in the game for sure. Although there are only three of them, one of them contains the infamous Banjo-Kazooie Ice Key! 
 

Game Pak #1

Return to Spiral Mountain when you have both the Airborne Egg Aiming and Grenade Eggs abilities mastered. Take to the air and fix your sights on the cracked screen covering the cave above the tree stumps. Blast it apart with a Grenade Egg and touch down inside the cave to find the Pink Special Egg. Heggy will hatch this egg for you, provided you ask nicely. This will unlock your Skinny Bird Bash ability. Don't ask. You gotta try it for yourself. 
 

Game Pak #2 
This Game Pak is also in Spiral Mountain although is a little less obvious. Fly over the waterfall and enter the cave from which the water flows. This leads to an area appropriately titled "Behind the Waterfall". Follow the ledge to the smaller waterfall in the rear of the cave and Grip Grab the ledge to climb up behind this second waterfall. There you will follow a tunnel that leads around to the Game Pak within the cage. The Blue Special Egg can be obtained here. Return to Heggy's Hen House to have her hatch this one for you as well. Homing Eggs are your reward. 
 

Game Pak #3 
The final Game Pak is the most important of all as it contains the Ice Key! Head to the Jinjo Village area of the Isle O' Hags and head for the sandy area near the lower Jinjo Houses. Grip Grab the ledge that winds around the left side of the green rocks and enter the cave there. At the end of the cave will be the final Game Pak. Inside, you will find the fabled Ice Key. Follow the instructions under "Dragon Kazooie" to see what you can do with it.
 
 

Multi-Player Jinjo
Ok, all of this talk about Heggy's Hen House has likely got you wondering what is in that egg up top. Well, once you learn the Hatch move in Terrydactyland head back to Heggy’s place, Bill Drill the object on the Split-Up Pads, Split-Up ad have Kazooie Hatch it. Inside you’ll find a Jinjo that can be used when playing multi-player.
 
 

Drive Submarine on Land
Okay, this may be useless, but it's still kind of neat. Have Humba Wumba transform you into the Submarine in Jolly Roger's Lagoon. If you try to warp back to the Town Square, you will be told that submarines can't operate outside the water. Not true! You can take the sub manually up to the surface and drive up the slope. The underwater craft actually handles quite well on dry land. Sadly, you can't get up the stairs -- but you can hop into the pig pool and explore the docks at your heart's content.