What games do most people remember from the NES Classic? I think the answer for most people would be Super Mario Bros, Zelda, Metroid, and maybe something like Final Fantasy or Megaman. I don't think many folks delved into what might be considered outlier games such as this one which most people don't really have a consensus on how to pronounce.
As a kid I pronounced it Ass-tee-uh-nax but as it turns out (and forgive my ignorance) Astyanax is actually a mythological character from Troy and was the son of Hector (we all remember him, right.) The name Asyanax translates to "Lord of the City." Nice little bit of info there.
Anyway, the game Astyanax was one of the ones that very few people owned and much like many of the less popular games in the western world, it was far more popular in Japan than it was elsewhere.
It was a side-scrolling platformer of sorts and its story was pretty typical and / or unimportant. You are a high school student named Astyanax because your parents hated you and were hippies, and you get summoned to another dimension to rescue the Princess Rosebud and no, I am not making this up.
The game was pretty similar to a lot of other games in the fantasy genre at the time but it did have one particular nuance that made it different than the others: You had a power-bar on your attack that would slowly recharge, so it was actually more beneficial to time powerful strikes than it was to swing wildly at your enemies.
The game was pretty inventive in that you could change your active spell by pausing the game and then switching it. You had a fire spell and lightning one that would fire in all directions effectively killing all minor enemies on the screen and another one that would stop time giving you a real advantage against boss characters.
Overall it was a pretty great game but was plagued with one annoying aspect that was present in a lot of NES platformer titles in that if you were struck, it would make your character "jump" a bit forward or back and this resulted in you falling to an insta-death very frequently. This is the sort of "cheese" that encouraged me to throw many a controller across the room.