There are a bunch of early arcade games that tried to ape the success of Space Invaders. Some were fun, many were forgettable.
I've been playing Cosmic Guerilla on MAME and I think it's one of the very best of these early arcade shooters.
In the game the enemies are goatmen (according to the cabinet artwork) arranged in columns on the left and right hand side of the screen, where you cannot shoot them. The center of the screen is dominated by temples (laser guns? pyramids?), which represent your lives, and maidens (according to the cabinet artwork) that are guarding the temples.
The goatmen begin advancing towards the center of the screen, and when they reach one of the maidens, they drag them off to the side of the screen, removing them from the game, then begin the trek back to the center to abduct more. If eventually a goatman reaches one of your temples, he will try to drag the temple to the edge of the screen, and if he succeeds you lose a life. As the levels increase the goatmen move faster and fire more projectiles.
You have to juggle shooting goatmen on either side of the screen. Sometimes one goatman will get turbo charged and race in and abduct a maiden/temple at a high speed, and will keep stealing maidens until you manage to shoot him. Occasionally flying saucers will zoom in and try to shoot you, shooting it gives bonus points. A mothership sometimes flies across the upper screen and shooting it gives lots of bonus points.
One aspect of the game I wasn't prepared for is that each "level" brings new goatmen, but you never get more maidens or temples (you can win an extra temple/life as a points reward). As your maidens/temples get stolen, that's it, they don't ever come back. This makes it imperative that you shoot those marauding goatmen that are running off with your maidens. Every time they succeed defeat looms closer. This game does the "frantic and hectic" thing very well.
I have to say, this is one of the most addictive fixed shooters I've ever played, and I've tried to play all of them. I discovered it last night and woke up excited to play more.
My highest score so far is 4910, and while not much in almost any other game, for an hour or two of playing I'm pretty happy with it. I do look forward to getting better.
The ROM file does seem to be damaged. I get a warning in MAME stating that "There are known problems with this machine", and true enough, the game crashes on me sometimes. It will freeze and my score will start blinking and I can't seem to do anything about it. I'm using an older version of MAME so that might be the issue.
I will note that the name of the game is nonsensical and ridiculous. Take the promotional flyer for the game.
"Dodge the Guerilla!" What guerilla? "Protect your laser guns!" What laser guns? Is the player icon supposed to represent a temple, a laser gun, or an archer on a dragon? Because of the name I thought this game would be garbage, but it's apparently simply the victim of nonsensical marketing.