It’s not a great game. And it’s certainly not as good (or as colourful) as my playfully fiddled with end sequence screenshot suggests. But somehow, I enjoyed it.
It’s like a cut-down version of the old MSX Metal Gear, only with no sneaking. Each level is a sort of maze with slight puzzle elements, different enemy types (with different movement and shooting patterns), the occasional miniboss, and finishes up with a larger (usually artillery) level boss.
You can also swap your character for a female character at will, and she offers you the “bonuses” of shooting slower and being unable to use any secondary weapons (grenades, rockets, flamethrower) at all. It seems. If your man dies, she takes over. Hmm.
I can’t really recommend it highly, but it entertained me enough to complete it, so I suppose it was doing something right.