The game engine of Donkey Kong 64 is divided into several modes with different properties. There is a cheat code that allows you to change the mode.
Note: Modes 4 and 8 are unknown.
0: Nintendo Logo[]
This mode is only used right after you turn on the console. It includes the Nintendo logo, the Nintendo 64 logo and the short opening cutscene aka "the Donkey Kong song" and ends when the DK Rap is loaded.
Controls are completely disabled in this mode.
1: Opening cutscene[]
After you quit the game or watch three DK TV demos, this mode will be activated. Just like mode 0, this one lasts only until the rap comes up.
Controls are completely disabled in this mode. However, if you get into another map using Intro Story Glitch or the Warp modifier, you may be able to use the Start button to advance to the rap.
2: DK Rap[]
As the name says, this mode is only active during the rap.
Controls are disabled except for the Start button, which is used to get to DK TV.
3: DK TV[]
This mode consists of the demos for each kong. Every time one of these shows up, the kong's stats will be reset to a preset state. For example, if you quit the game and watch Diddy's demo, he will lose all Golden Bananas and colored bananas, but he will also obtain Super Duper Simian Slam and all other Cranky upgrades out of nowhere.
Controls are disabled except for the Start button, which is used to advance to the main menu.
5: Main Menu[]
Normally this is limited to the main menu (map 50), but Intro Story Glitch allows you to explore other maps and find some odd properties in this mode.
Like in all modes but Adventure, the auto-save feature is disabled. As long as you're in this mode, you always have full health and there is no way to lose a melon slice.
Controls are functional except for the fact that the Start button is disabled.
6: Adventure / Kong Battle[]
This is the only mode with an active auto-save feature. It automatically saves every time the screen fades out. This does not apply to Kong Battle, though. When you start a multiplayer match, the game remains in mode 5 during the screen fade until after the "save frame". Also, when you end a match, it changes back to mode 5 before the game can be saved.
Controls are fully functional.
7: Loading Game Over Cutscene[]
For some reason, the game changes to another mode for a few seconds when you quit the game. As soon as the Game Over cutscene shows up, it will go into mode 9.
Controls are completely disabled in this mode.
9: Game Over[]
This is used during the Game Over cutscene.
Controls are disabled except for the Start button, which is used to get back to the opening cutscene.
10: End Sequence (Adventure)[]
This includes the two secret ending cutscenes, which are only shown if certain conditons are met.
Controls are completely disabled in this mode.
11: DK Theatre[]
All cutscenes in DK Theatre except End Sequence use this mode.
During the cutscenes, you can only use the A button to go back to the menu. However, at the end of Intro Story, you can speed up, skip, or slow down the Squawks text. Also, DK Theatre triggers an automatic DK screen fade about two seconds after the final cutscene ends. In that timeframe, you can do some basic actions such as punching. The Start button and the control stick are disabled, though.
12: DK Bonus / Bosses[]
This mode includes any bonus game or boss fight that you enter through the mystery menu.
Certain moves are automatically given to the kong at the start to make sure you can beat the game or boss. The start menu is simplified so it only has the options "Return" and "Quit Game". Any screen fade in this mode brings you back to the main menu (map 50), no matter what triggers it.
Controls are fully fuctional.
13: Snide's Bonus Games[]
This mode is very similar to mode 5. It is only used for Snide's bonus games, or inside the Test Map if you do the wrong warp.
Like in all modes but Adventure, the auto-save feature is disabled. As long as you're in this mode, you always have full health and there is no way to lose a melon slice. A "restart trigger" will reload the current map, whereas a "quit trigger" will send you back to Snide's H.Q. (map 0F).
Controls are functional except for the fact that the Start button is disabled.
14: End Sequence (DK Theatre)[]
Unlike in mode 10, the secret ending cutscenes are disabled in this mode.
During the first cutscene, you can only use the A button to go back to the menu. The scene inside DK Island allows you to do basic actions such as punching and using instruments and weapons, depending on whether you unlocked them in the current file. The control stick is disabled, though.