"Each copy of Hang-On includes one free copy of this perfectly cromulent shmup!"
Astro Warrior, released in late 1986 as a standalone game, is shockingly slight. That's not necessarily a bad thing for a first party Sega shmup sitting in that .zip directory full of Master System games you "found" online, but the idea of paying a new game price for Astro Warrior is comical. So much so, in fact, that Sega cottoned to this truth internally; thus Astro Warrior is more likely to be found bundled with Hang-On, the platform's first game. Such was how I came across this game in the wild.
As export SMS "launch window" fodder, Astro Warrior checks off the necessary boxes. The sprites are nicely animated and colorful, the framerate is buttery smooth, and the action controls well enough. What dings the game is its relative lack of depth. Powerups (speed boosts, weapon power, and two options) drift down center screen at fixed intervals with no input from the player beyond not dying. These powerups may at first be mistaken for enemies or, in the case of the options, enemy rounds, but eventually you'll learn to spot them. Once the player is fully powered up, as long as they avoid being shot, the boss of the third level is reachable in maybe ten minutes. After that, the game rolls to the first level and repeats. That's three levels and a power plateau obtainable in about three minutes. Again, the value proposition here is a little pants.
Still, Astro Warrior is a well controlling vertical shooter with nice sprites and a good sense of speed. It is ultimately outdone on the visual showpiece axis by the likes of Star Soldier on the competing Famicom, which came out a few months earlier. I can't recommend the standalone MyCard release at any price beyond a sort of sick completionist impulse, but the combo cart with Hang-On (a great SMS title) is worth grabbing.