Some time in the second half of the 1980s, I remember playing a video game on the Nintendo Entertainment System, and for many years I had thought the game was Wizards & Warriors II. There had been a short article about it in one of my friend's issues of Nintendo Power, so I think we decided to rent it for a weekend. However, since I have seen gameplay videos of Ironsword: Wizards & Warriors II, I realize that it must have been a different game—although the gameplay was similar.
As I said, my recollection is that this was an NES game from the later part of the 1980s, probably a year or two after the 1987 release of the original Wizards & Warriors. However, since my memory is apparently not reliable, it is conceivable that we actually played this game several years later in the 1990s on the SNES.
What I remember of the side-scrolling gameplay was that it was similar to Wizards & Warriors, featuring a character armed with a sword, fighting their way through various environments. I think there was less platforming and exploration than in Wizards & Warriors, making this game more like, say, Rastan. The advancement was divided into sub-levels (along the lines of those in the NES Ninja Gaiden), and I think that at the end of each sub-level, there was a (not too difficult) mini-boss. Then, after completing the two to four sub-levels that made up a full level, there was a much more difficult boss fight. The bosses got their own screens where they were fought; I think the environment in these boss arenas was just flat ground with a black background (or maybe just dark, with the scenery only faintly visible) behind the combatants. Of the bosses (or maybe mini-bosses) over the first few levels, I think there was one that was mostly blue and appeared to use lightning attacks. Another one was a golem-like stone figure, and you had to hit it when it exposed its pink brain in its midsection to do damage.