If the NES was good at anything, it was action side-scrollers, a genre that's pretty tough to screw up. Unless you put it in the hands of one of the most mid tier game developer/publishers of the 1980's and 90's, Jaleco (in my humble opinion, at least). Then your final result is something like Astyanax, a game that...certainly exists. 

Originally released in arcades as THE Astyanax, the Nintendo Entertainment System version was published and developed by the aforementioned Jaleco, seeing a release for the 8-bit system in the US in 1990. It's a simple and straightforward hack-n-slasher where you play as the titular Astyanax (which depending on the telling of the story, Astyanax was the Greek son of Hector who was killed by either being thrown from a wall during the fall of Troy, or the infant's body was used to club the King Priam to death by Odysseus. Great, thanks.

The NES port is naturally a visual and graphical downgrade, and is only single player. Changes from the arcade version include the ability to wield other weapons and magical spells. Astyanax's default weapon, the Bash, can be upgraded to a spear, a sword, and an axe. You can select between magical spells by pausing the game. This feels rather iffy and clunky, not too impossible, but just counterintuitive enough be annoying. 

Speaking of the Bash, Asytanax's attack power is determined by how rapidly you choose to strike. This does add some strategy to the game. You can wail on monsters, but it takes longer to chip away at their health, or let the power meter charge back for maximum strength. The problem is, Astyanax's god-awful lack of agility and being such a hulking sprite means constantly putting yourself in danger just to land a clean blow. Topped off with some of the most suspect hit detection, this takes a game that technically sports a pretty progressive attack system and makes it a plodding mess. I'd rather just burn through magic and save my health for boss fights than trying to coin the practice of fruitlessly chasing airborne enemies, just to get them off of you. The game's difficulty is pretty respectable, and escalates in a fair manner, with some decent-looking bosses. The action itself is just not stimulating or diverse enough.

As a kid, I thought the visuals were kinda cool. It's got larger sprites, the enemies are fine, and the bosses resemble Greek mythos well enough. As I got older, it actually comes off rather generic. The colors are overly saturated and brightened to barf-inducing levels. While the sprites are huge, the animation is quite pathetic, even by NES standards. Astyanax has some horrid graphical latency and flickering because everything is so gigantic. Just simply being big isn't engaging, it only highlights the limitations of the hardware, working against it. There's no distinctive sense of style, like Castlevania's stages and layouts, everything in Atsyanax comes off looking very flat and uninspired.

Being one of the earlier NES action games that had lengthy cutscenes, Astyanax is trying to convey its story of a young man donning the mantle of the hero to save a princess from the vicious Blackhorn (sounds like the name of an 80's death metal band) with the aid of the fairy/sprite, Cutie. The story has a cheesy charm to it. Unlike Ninja Gaiden, these talkie segments aren't artistic or visually evocative. Characters just talk slow, cycling through the reused headshots. The point certainly gets across, on a Saturday morning cartoon level.

Is Astyanax a BAD game? Ehhh, it mostly just feels...okay. I think this was a game that made its way through most kids' NES collections at one point, like T&C Surf Designs: Wood & Water Rage and The Legend of Kage; something that was experienced, and may have resonated with a few, but not really among the Nintendo's more memorable pieces of software.  

The music is pretty cool, and it's not an overly long game (six stages). I consider it one of the upper quality titles under the Jaleco library, which puts it in the middle of the road behind significantly better action games on the platform.