No doubt this is a hard shooter and frustrating one to boot. Enter at your own risk.
First the good. It is a direct translation of an arcade game and a great one to boot. It is intense and the screen sometimes is filled with bullets and enemies. You have a good selection of firepower and a screen clearing bomb to help you. Powerups come to you from a capsule that spread them along the screen. The bomb itself has to be charged in order for you to use it, so you have to stop firing your main weapon. This add an extra layer of depth in the risk vs. reward department. The level designs aren't bad except for the sixth one, but more on that later. It scrolls along smoothly with layers of parallax; quite a feat for the PC Engine back in 1990. There is also minimal flicker and no slowdown. The bosses are also creative in their design and offer more than enough challenge.
Now the bad. The ship's control seem a little imprecise at times. This isn't so troublesome for the first five levels, but is hazardous in the sixth level. Sometimes you have a gap just big enough for your ship to get through. Couple that with the auto scrolling and the enemy projectiles and you have a wafer thin window of opportunity. More often than not, you die because of this imprecise control. And in a game where you have limited continues, you waste a lot of lives here. Also, a lot of the times the screen fills with clutter, making difficult to maneuver. When you die, you are back to your pea shooter, which doesn't stand up too well with the onslaught.
Bottom line: This would be a great shooter if dying weren't so commonplace. The screen gets so cluttered sometimes and the imprecise control kills it. If the difficulty and frustration don't put you off, then give it a try. Not recommended for the casual gamer.