The Limits of Game Percentage

In DK64, the game percentage counter is based off assigning certain types of collectables a percentage. The values of which can be found here: https://dk64.fandom.com/wiki/Game_Percentage (Note that Rareware Banana seems to be responsible for ticking the counter to 101% in standard play, we're not sure if this means it's worth more than the standard 0.4%).
We'll be primarily focusing on the Golden Bananas (GBs) here, which increment the percentage counter by 0.4%.
In standard play, you are meant to only collect up to 201 GBs, which means that Golden Bananas give you 80.4% in regular play.

Due to the way the game stores GB counts in a save file (each kong for a level getting 3 bits of data. Values can range from 0-7), you can only ever have up to 7 GBs for a kong before the game starts looping back round to 0 for collecting more:

GBs COLLECTED | GBs SAVED
--------------|-------------
0             | 0
1             | 1
2             | 2
...           | ...
7             | 7
8             | 0
9             | 1
10            | 2

Given that there are 8 levels in the game where you are intended to collect GBs, you can collect up to 280 GBs. This means that you can get a maximum of 112% from GBs with various glitches. Adding the percentages from the rest of the collectables totals the game percentage up to 132% (Displayed as -124% due to integer overflow).

That being said, there are slots in the game's memory for 6 other levels in the game (Helm, Bonus, Multiplayer, Story, Test, Shared [Eg. Troff n Scoff]) as well as slots for Krusha's GBs in the 14 levels.

Unfortunately, Krusha's GBs do not increment the GB counter (even the GB counter on the pause menu), so we immediately rule out the 98 GBs you could get from him. However, that's not all regarding the DK64 heartbreak, the 6 additional levels' counts do not save either. This rules out the 210 GBs we would get from that, leaving us back with the count of 280 we had before.

So, the limit of the GB count is 280. No way of getting past that without breaking the save file structure. What about everything else?

The totals of everything else that affects the percentage counter is based off totalling the amount of flags set in that category. So collecting key 5 twice (if it could be done) would not give you a 9th key to your counter since you would not be setting any additional flags in the key set.
Nintendo Coin: Based off a flag, limited at 1 Coin
Rareware Coin: Based off a flag, limited at 1 Coin
Medals: Based off flags, limited at 40 (It is theoretically possible to get 75 Bananas in the other 6 levels, but these don't set any flags)
Fairies: Based off Flags, limited at 20
Crowns: Based off flags, limited at 10
Keys: Based off flags, limited at 8

In theory, one could say "just find Key 9". So I set every flag in the game, and none of the above totals increased at all. So these are the limits. Also, the hidden Ice Key inventory slot does not increment the percentage counter either.

In conclusion, Max% is not getting past 132% unless we break how save data is stored or break how the percentage counter works. However, if you're like me and like to dream of a world where DK64 is a little more broken, here are some stats:

WHAT IF
Everything counted and Saved: 588 GBs, 255.2% (-1%)
Everything that increments the pause counter saves: 490 GBs, 216% (-40%)
The real world: 280 GBs, 132% (-124%)