X Multiply

By the late eighties Irem had a reputation for producing the most visually inventive shooters in arcades, and X Multiply from 1989 supports it. This is a horizontally scrolling action game set inside a biological environment, where you fly through an organism among fleshy walls, tentacles and parasites. At a time when most shooters were sending metal ships through space, that was a sharp departure.

The defining mechanic is the pair of tentacle arms trailing from your craft. They behave semi-automatically, swinging according to how you move, and they function as both a shield against incoming fire and a close-range weapon. Learning their behaviour is essential, because the game is built around narrow passages where your movement is restricted and badly angled arms mean taking a hit.

Level design is uncompromising and assumes you will memorise it. That was standard for arcade shooters of this vintage: the game punishes any attempt to improvise through a section, but it also gives clear feedback about what killed you, so each attempt genuinely carries you further than the last.

Visually X Multiply remains striking. The backgrounds are detailed and organic, the enemies are as unpleasant as intended, and the animation is smooth throughout. The audio matches the theme, staying close, pulsing and largely uninterested in conventional melody.

It runs here directly in the browser through MAME emulation, with nothing to install. Single player, and definitely not for the impatient.