Have you ever played a game that was so much like another game that you just took for granted that it was part of a series only to realize later that is isn't?
I figure this happens for a few reasons. It could just be people ripping an established formula off, or it could be teams or individual programmers who were involved with the previous titles and just work for another company now.
This topic was inspired by the recent topic asking about compilations that you would like that were never made. I was thinking about the Rolling Thunder games. There's Rolling Thunder, Rolling Thunder II and there was a game I remember playing back in the back a few times called Rough Ranger that I assumed was a part of the series because it's so much like the original Rolling Thunder. Well, I haven't seen the game in over 20 years so I looked it up and it seems it was released by a different company and seems to have nothing to do with the series, besides ripping and palette swapping sprites, animations and play mechanics.