Even if the games Debug Mode cannot be activated without an N64 development console unit, there still appears to be some test features left in the games code. Most of them are only visual, and were (perhaps) possibly used during the games development for testing the models ingame appearance.(i could be wrong though, they may not even be debug at all)
Debug feature 1
XX is 00 by default
01: Disables some parts of certain character models(easily noticeable on Conker, his top eye textures is invisible, allowing you to see the rest of the eye region.)
04: Texture strecthing disabled on most models.
05: value 01 – 04, combined
Debug feature 2
XX is 00 by default
04: Basic character shadows disabled. A few 2D sprites also seem to be affected.
Debug feature 3
XX is 20 by default
24: Texture details in Background box is now displayed as differently coloured square tiles.
40 to 70: Rooms(not counting outside areas) become darker.
NEW: Crash Debugger Values:
if set to 01 or higher, the crash debugger will be entered. Setting it back to 00 and picking retry code will resume the game. Likely an variable once used by the debugging team at Rare, and they probably needed access to the debugger if something gone wrong during testing.
Unknown. Doesn’t seem to do anything in the retail game.
this address is always set to zero by the game, no matter if an GS code forces it to set 01 or some other value. What this one is about, I can’t really tell.
Level Appearance Scaling:
Beyond the Screen Display:
Rather neat, strange, may even trigger epileptic seizures, but also a bit interesting. This normally cannot be seen, but underneath the screen display is an framebuffer of some kind, which shows the frame that were previously drawn at the top side for about a few milliseconds before being updated with a new frame, which goes on like this. Basically, the top area is constantly updated, with the bottom area showing the previous frame. This will not work on emulators however, because the bottom part is never emulated properly, leaving it showing only some artifacts, or just black space.