Whenever smart-alecks try to claim that the Odyssey² wasn't a very good video game system, this is the game they like to trot out. Yes, it's a Space Invaders knock-off. No, it's not as good as Space Invaders. Yes, the word "Plus!" in the U.S. title sounds pretentious. But in 1981, O2 owners across the world were in love with this game.
I can say this with authority, because I was one of them. I clearly remember playing this game and simply being unable to put it down. True, I was six years old in 1981 and easily impressed, but I maintain that the game wouldn't have held my interest that long if it had been completely terrible. It is indeed a Space Invaders clone, but unlike some other knock-offs, this one at least has some innovations.
In Space Invaders, the aliens form a rectangular phalanx that employs the deadly military technique of moving from one side of the screen to the other, and gradually dropping down toward the ground. In Space Monster+, invaders lined up in a single row "bounce" back and forth in place, and don't descend. OK, it's an invasion where nobody actually invades, but that doesn't mean the aliens aren't dangerous.
Each alien mans a cannon. The cannons, naturally, are the source of enemy fire. If you destroy a cannon, the alien behind it becomes harmless. And if you manage to take out an alien without hitting its cannon, the weapon is neutralized. Hitting either target is more difficult than in Space Invaders because the invading fleet is sitting behind an indestructible shield. You have to shoot through gaps in this shield – and between your own ground-based bunkers – to hit anything.
Of course, the most prominent feature of this game – which dominates the American box art and inspired the title of the European release – is the "mothership" at the top of the screen. The huge, tentacled monstrosity is smarter than the run-of-the-mill invaders and is surprisingly adept at avoiding your shots. You must destroy it to win a round, but if you hit it while other invaders are still alive, it'll just reappear in a few seconds. However, if you take out the other invaders first, it will descend to the area just above your ship, which makes it really tough to hit. (I also distinctly remember cursing the darn "bird," as I called it, at age six.)
The other innovation of Space Monster+ is evident when you are hit. Surprisingly, you don't immediately die. Instead, your ship disintegrates, leaving you in control of a little green robot pilot. If you manage to run under one of your bunkers before being hit again, you can dismantle that bunker to obtain a new ship. This is at least a bit more sporting than the one-hit kills of Space Invaders.
With all these innovations, it may sound like Space Monster+ is a better game than Space Invaders. Unfortunately, it isn't. Every round plays pretty much the same, and becomes rather tedious after a while. Once you get the pattern down (not difficult to do unless you're six years old), you'll breeze through most invasions with no problem. Only facing the monster will give you any challenge at all, but it's too little, too late. It's not hard to understand why people like to pick on this game; it didn't really do justice to its arcade inspiration in the first place, and it certainly hasn't aged well. Nevertheless, it's not completely worthless. At least Magnavox tried to innovate with it. When the game came out, it really was fun, and that's a success by any definition. But I'll admit that the "Plus!" was a bit much.