I always considered VCS marvel at engineering but, at the same time, it was always to constraining for me so I settled for less perfect but much more capable Atari 800. Some recently released VCS games seemed to achieve impossible. Quickly I found that some of the games have even more help from the cartridge than what was available back in the day in the form of Display Processor Chip (as used in Pitfall II). In those games it is ARM processor, hidden in Harmony / Melody cartridge, which does the heavy lifting and original CPU (6507) tries hard but can not really keep up. This led me to the following question: Would it make sense to plug in Harmony-like expansion in place of the VCS original CPU?