Some of you may remember a series of peculiar Game Boy Advance games that came out over the course of 2004. In stark contrast with the usual dark grey cartridges with colorful labels, a set of light grey cartridges with simple labels were released containing games ported from the original Nintendo Entertainment System. Dubbed the Classic NES Series in the United States, these games were interesting for a number of reasons.
From a GBA emulation perspective, the games were especially interesting. The average Game Boy Advance game is extremely buggy, and the platform itself contains a number of safeguards to prevent games from crashing. As a result, emulators tend to need to be bug-compatible with the original hardware to ensure that the games actually work. However, the Classic NES Series goes above and beyond the average game in an attempt to ensure they don’t work in emulators.
If you’ve tried to load one in some older emulators, you’ve probably been confronted with a Game Pak Error screen, as seen above. As it turns out, these games exploit several tricks and undefined behaviors that make emulating them challenging. This appears to be a deliberate attempt to dissuade copying these games. In the interest of accuracy, I have painstakingly investigated, implemented and chronicled all of the unusual things I’ve found these games to do.