Killer Ring is a subtle variation on the Phoenix stand-alone arcade game: after shooting waves of aliens, you must shoot your way through a barrier to kill the "wotsit".
In Killer Ring, the wotsit is an alien being surrounded by a force-field. To kill him, you must shoot through its base - the rest of the field is impenetrable. This base covers a rotating shield, which can also be breached by successive shooting. Once through the rotating shield, you must shoot the green alien's red heart.
The preceding levels, all six of them, take the usual form of alien cremation. Levels one and two give you floating bats to fire at. Three and four have an extra distraction: a group of flying saucers flitting about the screen bombing you. The floating bats are replaced by rotating spheroids which you can kill only by shooting through one of the two gaps in their shield. The last two levels take the form of moons oozing yet more bats - this time in magenta!
Your ship, as the title suggests, is a ring - very vulnerable with little shielding.
Amazingly, Killer Ring has a funny addictive quality initially. The interest wanes as quickly as the moons in levels five and six. The game's biggest detraction is its lack of difficulty. The writers tried to compensate this by including a "Difficult" mode. But having completed the Easy mode, the Difficult mode gave me no real trouble.
Graphics are good and the characters are well defined. Sound effects are also above average, and the music is very good. In conclusion, a pretty game - pretty indifferent!
Second Opinion
This is a game that's extremely satisfying - or rather, relaxing - to play after a hard day's work. You just sit there and shoot. It doesn't matter that you can easily get high scores or even that there arc only seven levels. Killer Ring is enjoyable and just the tonic when a mindless task is all you are capable of.