I've heard stories like those sticky notes. People had a somewhat similar problem with Half-Life, with a single mechanic, but they managed to eliminate it from the equation and glue two pieces of code together. From what I've heard, this was a fairly common practice. Especially since programmers like Gabe Nevell and John Carmack often sat after work hours and tested every solution they could think of. Did something work? Did the tests confirm it? Then we write the solution down on a piece of paper... Or maybe not, and then think in that jumble of code about what the author meant :D.

Oh yes, porting games from archaic platforms is a problem. Besides, some PS1 games were difficult to port due to their technological limitations. I don't remember the details, but some/many PS1 games had some graphical limitations.