I have been reverse engineering a 25-year-old proprietary (PlayStation 1 based) system used in a number of well-known arcade games for almost a year, digging in

I have been reverse engineering a 25-year-old proprietary (PlayStation 1 based) system used in a number of well-known arcade games for almost a year, digging into every single detail and uncovering what even MAME developers ignored. The end purpose was initially to enable homebrew game development but, with the prices these boxes are fetching on the used market, I know nobody is ever going to bother. Moreover, as far as reverse engineering existing games goes, the most interesting parts (i.e. the copy protection) have already been figured out two decades ago and most of the games are perfectly playable through emulation. Still, reverse engineering an unknown platform that isn't too serious about security is fun and rewarding.