Posted on May 21st, 2019 by Jeremy Meisnitzer
Developers were short on space due to the limited nature of the NES cartridges and recycling assets was a great way to save space.
The size of NES games was on average between 128 and 384 KB. Although some went as high as 1 MB that is still 50,000 times less than what you can store on a Blu-ray disc. Storage capacity was low and any trick to free up space was immensely useful, so can we really blame them for doing a recolour?
To put this into perspective the image of Super Mario Bros. at the start of this page is 186 KB, which is larger than a lot of NES games.