Suffice it to say, it's a 28k LOC file that was so bad, it could even hold up in court as evidence that a South American company stole the code of Zynga's -ville games. We could reproduce each and every single bug and its effects 1:1 in their games, with all the crashing scenarios that were easy to reproduce, hard to debug, and almost impossible to fix.
Once you dig into the hole of depth sorting and being smart by "just slicing" everything into squared ground tiles on the fly, there's no way out of that spaghetti code anymore.
Fun times, was always a joy seeing people give up to a single code file. The first step to enlightenment was always resignation :)