Neatly programmed but essentially dull shoot 'em up based around a 3-D isometric grid. With your little plasma ball, you shoot positive energy at negative ions (they don't like it much, fortunately) and then, at the end of each mini-wave, you shoot even more positive energy at 'IT', a large thingy that follows you around the screen like the rozzers when you're doing 125 in a built-up area. If this sounds just like the usual plot to every shoot 'em up, except transferred from the usual scrolling format to a Head Over Heels room, you'd be dead right - except that Plasma Ball lacks the variety and pretty graphics of all but the meanest zapper. Nevertheless, the movement of your ball - inertia-based - is satisfyingly smooth, which for hardened pyschotics may make up for the game's other flaws. Not for me though.