You can see what the menu looked like here, pretty damn awesome! We just need somebody to try and get it working from inside of GDMENU.
Browsing cheat codes list

Enabling codes for a specific game

Crazy Taxi 2 has codes on and is enabled

Selecting add game from the sub-menu

Editing new game title

Adding a code to the newly created title

Setting new code description

Selecting edit code option

Viewing/editing code values

We were discussing this over here,
https://assemblergames.com/threads/unof ... ost-983617