Source: Wikipedia, "Rezon", available under the CC-BY-SA License.
Taking place in the year 2191, the player pilots a recently developed space fighter, the SR-91, through six stages to defend the Earth from a two year long alien invasion. The SR-91 uses the VAWs (Variable Armor and Weapon System) which uses the Optica Weapon Arms. The Arms shield the ship from top and bottom attacks, provides back-up fire and using its Arm System can be positioned to fire in 90° angles behind and around the ship. The player could also have the VAWs spread out providing wider shots. The SR-91 could use one of three different pick-up weapons including the straight firing Laser, the wide-firing Ring Laser or the rebounding Ball Shot; the only other pick-up items were Speed Ups and Speed Downs. Extends were set at the first 70,000 points and was added with every 80,000.