Astyanax is a scrolling video game initially released in the arcades (titled The Astyanax), and later ported to the NES. The two games each have a different plot, with the arcade version revolving around the warrior Roche and the NES version around a sixteen year old named, appropriately, Astyanax who has recurring dreams of a princess shouting for help. One thing follows another and he inevitably sets off on his quest to save the princess he has seen in his dreams.
In this video game, the player character's goal is to walk right and fight hordes of oncoming opponents. His abilities consists of jumping, attacking with your axe and performing a magical attack that is executed with a combination of the jump and attack buttons (a and b, respectively).
Interestingly, the power your attacks will deliver depends on how fast you execute your attacks. If the player wishes, he can rapidly mash the attack button in order to use his axe continuously without stop. However, the more he does this the less attack power the axe will have. If he waits, the power bar will start to regenerate and his attacks will once again be very powerful.
The NES game, while graphically downgraded from the arcade version, did feature impressively large graphics. This, however, caused an unappealing amount of flicker.
It has been speculated that the attack system mentioned in the second paragraph of "gameplay" influenced a very similar system used in the ultra popular Secret of Mana on the SNES by Square Enix. Of course this has not been confirmed, though it is very likely.