It's good! Very clean-looking and -controlling shmup with some interesting stuff going on. You're protecting each one of the planets in the solar system from alien attack--which is actually racked up as a percentage throughout a "stage" (broken up into 3 areas) based on how many enemies you let escape. The percentage is then used in a scoring formula at the end of each planet; and of course, if you let it get to 100%, it's game over.

The gameplay, as aforementioned, is straightforward and tight, with well-thought-out enemy spawns and patterns in general, especially for 1986. The problem is that completing a loop takes too long--45 mins to an hour--and that during that hefty runtime, you're bound to notice myriad (by themselves minor) design nags that add up to a pretty significant drag on the experience.

Power ups vacate the screen very quickly, often baiting you into deaths as you try to micrododge oncoming fire to retrieve them (add to this that you cannot grab an item while invincible from bombing). You start each life at base power, making recovery agonizing late in the game (not only is your ship slow, but it accelerates extremely slowly until you get one speed power-up, making for many an awkward, unfun time). And finally, your hitbox is very big -- common for the era, sure, but so much about this game feels so unclunky and surprisingly moden, so I'm just bummed it wasn't ahead-of-its-time in this area too.

Again, for 1986, this is downright impressive, and the guy who designed it would go on to program one of Taito's most beloved and successful games, Bubble Bobble. Give it a try if you're interested in the shmup genre's deep cuts!